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65,248,561 | https://en.wikipedia.org/wiki/Sebka | Sebka () refers to a type of decorative motif used in western Islamic ("Moorish") architecture and Mudéjar architecture.
History and description
Various types of interlacing rhombus-like motifs are heavily featured on the surfaces of minarets and other architectural elements in Morocco and al-Andalus during the Almohad period (12th–13th centuries). They continued to spread to other decorative mediums such as carved stucco over the walls of various buildings in Marinid and Nasrid architecture, eventually becoming a standard feature in the western Islamic ornamental repertoire, often in combination with arabesque elements.
George Marçais, an important 20th-century scholar on the architecture of the region, argues that this motif originated with the complex interlacing arches in the 10th-century extension of the Great Mosque of Cordoba by Caliph al-Hakam II. It was then miniaturized and widened into a repeating net-like pattern that can cover surfaces. This motif, in turn, had many detailed variations. One common version, called darj wa ktaf ("step and shoulder") by Moroccan craftsmen, makes use of alternating straight and curved lines which cross each other on their symmetrical axes, forming a motif that repeats shapes resembling roughly a khamsa, fleur-de-lis, or palmette. Another version, also commonly found on minarets in alternation with the darj wa ktaf, consists of interlacing multifoil/polylobed arches to form a more rounded lobed shape.
References
Architecture in Morocco
Islamic art
Visual motifs
Moorish architecture | Sebka | [
"Mathematics"
] | 327 | [
"Symbols",
"Visual motifs"
] |
65,249,333 | https://en.wikipedia.org/wiki/Wirthbacteria | Candidatus Wirthbacteria is a proposed bacterial phylum containing only one known sample from the Crystal Geyser aquifer, Ca. Wirthibacter wanneri. This bacterium stands out in a basal position in some trees of life as it is closely related to Candidate phyla radiation but is not considered part of that clade.
See also
List of bacteria genera
List of bacterial orders
References
Bacteria described in the 21st century
Candidatus taxa
Bacteria phyla | Wirthbacteria | [
"Biology"
] | 98 | [
"Bacteria stubs",
"Bacteria"
] |
65,249,555 | https://en.wikipedia.org/wiki/SB-228357 | SB-228357 is a drug which acts as a selective antagonist of the serotonin 5-HT2B and 5-HT2C receptors.
It has antidepressant and anxiolytic effects in animal models and inhibits 5-HT2B mediated proliferation of cardiac fibroblasts. It has also been found to reverse meta-chlorophenylpiperazine (mCPP)-induced hypolocomotion and to attenuate haloperidol-induced catalepsy.
The drug was under development by GlaxoSmithKline for the treatment of major depressive disorder and anxiety disorders. It reached the preclinical research phase of development. However, development of the drug was discontinued.
See also
RS-102221
SB-242084
SB-243213
References
5-HT2C antagonists
Abandoned drugs
Indoles
3-Pyridyl compounds
Ureas | SB-228357 | [
"Chemistry"
] | 200 | [
"Pharmacology",
"Drug safety",
"Medicinal chemistry stubs",
"Organic compounds",
"Pharmacology stubs",
"Abandoned drugs",
"Ureas"
] |
65,251,531 | https://en.wikipedia.org/wiki/Hildegard%20Lamfrom | Hildegard Lamfrom was a German-American molecular biologist/biochemist. She helped develop one of the first in-vitro translation systems, using rabbit reticulocyte lysate to study protein synthesis (a process called translation) in a cell-free context. This allowed her to make a number of contributions to the field including providing some of the first direct evidence for the existence of messenger RNA (mRNA) as a protein template, as well as the existence of polyribosomes (aka polysomes) (multiple ribosomes translating on the same mRNA).
Early life and education
Lamfrom was born into a Jewish family in Augsburg, Germany, in 1922, the eldest of three sisters (Gertrude (Gert) Boyle and Eva). Her family fled Germany in 1937, when she was 15, and established themselves in Portland, Oregon. Her father, who had owned a shirt factory in Germany bought a small hat and cap company that the family grew into Columbia Sportswear. Her sister Gert Boyle would later run the company and become an entrepreneurial icon, later donating large amounts of money to cancer research in her sister's honor.
Hiledgard graduated from Grant High School in Portland. She then attended Reed College and financed her education by working in shipyards as a welder. She earned a BA in biology from Reed and did research on avian malaria with Ralph Macy. She then earned an MA from Oregon State University. She was accepted to Western Reserve (now Case Western Reserve University)'s medical school, but decided to focus on research. She studied the renin system with pathologist Harry Goldblatt at Case Western and earned her PhD in 1949.
Career
Lamfrom went with her PhD advisor Harry Goldblatt to Cedars of Lebanon Hospital in Los Angeles. There, she continued to research the renin system for five more years. In 1955 went to study at Copenhagen's Carlsberg Laboratory on an American Heart Association Fellowship, working in Linderstrom-Lang's department. In 1958 she moved to Caltech where she did research with Henry Borsook. Here at Caltech, with Richard Schweet, she was able to help work out an in vitro system for studying hemoglobin synthesis in rabbit reticulocyte lysate. In this research, Hildegard was one of the first investigators to provide experimental evidence for the existence of messenger RNA, an informational molecule that directs the sequence of amino acids generated during protein synthesis. From 1962 to 1965 she continued research on protein synthesis at the MRC Laboratory in Cambridge, England, working with Francis Crick and Sydney Brenner. She then went to work at the Institut de Biologie Physico-Chimique in Paris (1965-1967). She went on to collaborate with her close friend Anand Sarabhai at the Institute of Molecular Biology in Eugene, Oregon from 1967-1970. The pair then researched in UCSD's chemistry department, where they collaborated with John Abelson to study tRNA synthesis. In the 1970's Lamfrom and Sarabhai spent extended periods of time in India and established a research laboratory called Biocenter. The last two years of her career were spent at Harvard Medical School, working with Tom Benjamin studying the involvement of middle T-antigen in tumor induction.
Research
The beginning of Lamfrom's career was spent studying the renin-antirenin system with pathologist Harry Goldblatt. She then shifted to studying protein synthesis. Working with Richard Schweet at Caltech, and later with Paul Knopf at MRC, she helped develop one of the first in-vitro translation systems, using rabbit reticulocyte lysate to study protein synthesis (a process called translation) in a cell-free context. This allowed her to make a number of contributions to the field. By mixing components of different animal cells, and showing that sheep ribosomes (protein-making complexes) could make rabbit hemoglobin and vice versa, she provided some of the first direct experimental evidence for the existence of messenger RNA and its role in determining what protein ribosomes make. She also was one of the well as the existence of polyribosomes (aka polysomes) (multiple ribosomes translating on the same mRNA). The last two years of her career were spent at Harvard Medical School, working with Tom Benjamin studying the involvement of middle T-antigen in tumor induction.
Personal life and honors
Lamfrom met her life partner, Anand Sarabha, in India. They hosted artisans, leading to unique collaborations. Lamfrom died from a brain tumor after nine months of illness on August 28, 1984, in La Jolla, California.
In 2015, Oregon Health & Science University (OHSU) named a biochemistry building in her honor. OHSU's Knight Cancer Institute provides Hildegard Lamfrom Research Scholar Awards to early-stage cancer researchers, with funding from an endowment established by her nephew, Tim Boyle, CEO of Columbia Sportswear, and his wife Mary. In 2010, her sister Gert Boyle gave an anonymous $100 million donation to the school in her sister's honor. Gert, Tim and Mary Boyle, donated $2.5 million to create the Hildegard Lamfrom Endowed Chair in Basic Science at the OHSU Knight Cancer Institute. Hildegard is remembered as an influential mentor to young scientists, including Brian Druker. In 2014, Tim and Mary donated $10 million to the Knight Cancer Institute at Oregon Health & Science University (OHSU) to create a mentorship fund in her honor.
Key publications
References
1922 births
1984 deaths
Women biochemists
Women molecular biologists
Reed College alumni
Jewish American scientists
Jewish emigrants from Nazi Germany to the United States
Carlsberg Laboratory staff | Hildegard Lamfrom | [
"Chemistry"
] | 1,189 | [
"Biochemists",
"Women biochemists"
] |
65,252,249 | https://en.wikipedia.org/wiki/Porostromata | "Porostromata" is an antiquated form taxon that refers to fossil cyanobacteria. The term porostromate is also used as a descriptor of textures and microstructure of stromatolites and oncolites which contain tubules or other cellular structures.
The group was defined by Pia (1927) as containing calcareous algae bearing calcified tubules; these may run parallel to the growth surface as in Girvanella, Sphaerocodium or perpendicular, as in Hedstroemia, Ortonella, and Mitcheldaenia; however, in 1937 Pia restricted the group to only Girvanella and Sphaerocodium, placing the other genera in the Codiaceae. In reality it seems that most or all of the species included in "Porostromata" represent fossils of cyanobacteria.
Monty (1981) advocated continued use of porostramata in an informal sense to describe a habit and structure of bacterial colonies, rather than in a taxonomic sense. He defined a "porostromate" microstructure as follows:"Porostromate microstructures are defined by the growth of loose or tangled, vertical, flabellate or flat-lying, straight or sinuous calcified filaments or threads, or even of calcified unicells."Porostromate stromatolites and oncolites are mostly absent throughout the Proterozoic, with calcified filaments apparently first appearing in the uppermost Precambrian. They then persist throughout the entire Phanerozoic, though from the Eocene and beyond they are only known from freshwater environments.
Stromatolites and oncolites not bearing clear cellular structures are referred to as "spongiostromate"; throughout geologic history they seem to have always vastly outnumbered porostromate forms.
References
Paleobotany
Cyanobacteria
Stromatolites
Trace fossils | Porostromata | [
"Biology"
] | 416 | [
"Algae",
"Cyanobacteria"
] |
65,252,408 | https://en.wikipedia.org/wiki/Spongiostromata | "Spongiostromata" is an antiquated form taxon that refers primarily to fossil cyanobacteria. "Spongiostromate" is also used to describe stromatolites and oncolites that do not preserve clear tubules or other cellular microstructure.
Pia (1927) erected the group to contain calcareous algal fossils that contain no visible cellular structure but which he presumed represented cyanobacteria based on comparisons to modern examples. He divided the taxon into two groups: the stromatolithi and the oncolithi.
Monty (1981) abolished the group as taxonomically uninformative but advocated for the use of "spongiostromata" to describe a form and texture of bacterial fossils. He defined a "spongiostromate" texture as follows:"Spongiostromate microstructures result from the individualization of micritic, spongious, fenestral, sparitic, pelloidal, detrital, etc. laminae or films, variously grouped and organized. "Throughout geologic history, spongiostromate stromatolites and oncolites have always seemed to vastly outnumber the porostromate forms.
References
Paleobotany
Cyanobacteria
Stromatolites
Trace fossils | Spongiostromata | [
"Biology"
] | 277 | [
"Algae",
"Cyanobacteria"
] |
65,252,533 | https://en.wikipedia.org/wiki/PokerGO | PokerGO is an over-the-top content platform based in Las Vegas, Nevada. PokerGO was launched in 2017 as a subscription-based streaming service, offering poker-centric online streaming.
The content offered on PokerGO includes poker tournaments, along with cash game-orientated shows.
As of February 2021, PokerGO's library of content includes over 2,400 videos totaling over 3,800 continuous hours.
Content
PokerGO includes shows, tournament replays, and cash games. Other media includes episodes, live-streams, and recap videos. Live-streamed events can be accessed as on-demand videos after.
Poker tournaments and cash games
High Stakes Poker
High Stakes Poker is a cash game poker television program hosting a mix of professional and amateur poker players playing high stakes No-Limit Hold’em with buy-ins ranging from $100,000 to $500,000.
The show debuted in January 2006 and initially ran for seven seasons till May 2011. In February 2020, PokerGO announced that they had acquired the High Stakes Poker brand and the show's assets. In December 2020, a new season of High Stakes Poker aired on PokerGO and included returning players Tom Dwan, Phil Hellmuth, Brandon Adams, and Phil Ivey, while also introducing new players to High Stakes Poker including Jason Koon, Jean-Robert Bellande, Bryn Kenney, Doug Polk, Michael Schwimer, and Chamath Palihapitiya.
There are nine seasons of High Stakes Poker and 126 episodes, and current hosts include Nick Schulman and A.J. Benza.
Poker After Dark
Poker After Dark is a poker television program that follows the development of one table of poker players over a period of time. The seasons are split into weeks with each given a theme based on the players involved. Poker After Dark originally began under a No-Limit Hold’em sit-n-go format before evolving to cash games that also featured different game variations such as Pot-Limit Omaha, 2-7 Triple Draw, H.O.R.S.E., or Short Deck.
The original series would see one table play over five episodes with the sixth episode being a director's cut. The show was acquired in 2017 and rebooted as a live stream show for four seasons before returning to the episodic format for season 12.
World Series of Poker
The World Series of Poker (WSOP) is a series of tournaments of most major poker variants that have been held annually in Las Vegas since 1970. The WSOP expanded to Europe in 2007, and Asia Pacific in 2012.
PokerGO acquired the global television and digital media rights to the WSOP in 2017. The agreement included the expansion of programming in a shared deal that saw live coverage on both ESPN and PokerGO. In 2020, WSOP Classic was added to the PokerGO library that included footage from both the WSOP Main Event and WSOP bracelet events from 2003—2010.
Super High Roller Bowl
The Super High Roller Bowl is a recurring high-stakes No-Limit Hold’em poker tournament held at various locations around the world since 2015. After beginning in Las Vegas, the Super High Roller Bowl has expanded to Macau, London, Bahamas, Australia, and Russia, as well as having an online event on partypoker in 2020.
U.S. Poker Open
The U.S. Poker Open is a poker tournament series hosted in the PokerGO Studio since 2018. The series features a variety of events at different buy-in amounts and crowns a series champion each year. Previous series champions include Stephen Chidwick (2018) and David Peters (2019).
Poker Masters
Held since 2017, the Poker Masters is a poker tournament series hosted in the PokerGO Studio. The series awards a Purple Jacket to the overall champion, and winners include Steffen Sontheimer (2017), Ali Imsirovic (2018), and Sam Soverel (2019). In 2020, the event moved online to partypoker, and Alexandros Kolonias won the championship.
Additional poker tournaments and cash games
Additional poker tournament and cash games coverage available on PokerGO includes:
High Stakes Duel
High Stakes Feud
PokerGO Cup
Dolly's Game
Rob's Home Game
Friday Night Poker
Super High Roller Cash Game
British Poker Open
Australian Poker Open
World Poker Tour
Partypoker MILLIONS
Aussie Millions
ARIA High Roller Series
Super High Roller Celebrity Shootout
Doubles Poker Championship
Face the Ace
Poker Central Celebrity Shootout
Original programming
Pokerography
Pokerography is a biopic series that tells the stories behind players and outlines their lives and poker careers. There are 23 episodes of Pokerography. Some of the players featured include Antonio Esfandiari, Chris Moneymaker, Jennifer Tilly, Mike Sexton, and Phil Hellmuth.
Super High Roller Club
Presented by Ali Nejad, Super High Roller Club is a six-part series that gives viewers a glimpse into the lives of poker players as they tell stories from the felt and from life. The players involved include Brandon Adams, Nick Schulman, Farah Galfond, Antonio Esfandiari, Phil Hellmuth, and Daniel Negreanu.
Real Talk
Real Talk is a roundtable talk show hosted by Remko Rinkema, who he discusses a wide variety of topics with poker players. The players involved include Scott Blumstein, Liv Boeree, Matt Berkey, Kane Kalas, Bryn Kenney, Bryon Kaverman, Justin Bonomo, Isaac Haxton, Maria Ho, Jason Koon, Greg Merson, and Mike Sexton.
The Big Blind
The Big Blind is a poker trivia show. Host Jeff Platt tests three contestants each week on their knowledge of Las Vegas, casinos, gambling, and poker.
Legends of the Game
Legends of the Game is a six-part docuseries providing a closer look at legendary gamblers and poker's most defining characters as Benny Binion, Stu Ungar, and David “Chip” Reese.
Dead Money
Dead Money follows poker professional Matt Berkey as he prepares to play the 2016 Super High Roller Bowl. Although predominantly a cash game player, Berkey is set to play his biggest buy-in poker tournament of $300,000, and Dead Money gives viewers a unique look into his strategy and decision-making on the way to him finishing in fifth-place for $1,100,000.
Additional programming
Additional programming available on PokerGO includes:
The Championship Run
Stories from the Felt
Deep Issues
Beyond the Rail
Major Wager
INSIDERS: Super High Roller Bowl 2018
2020 Hindsight
Hand Histories
Inside Poker
Poker Nights
Tell Tale
Chasing Hearts
Grinders
Device support and technical details
Devices
PokerGO can be accessed via a web browser on personal computers, tablets, or mobile phones, while PokerGO apps are available on various platforms, including Apple iPhone, Apple iPad, Apple TV, android mobile and tablet devices, Roku devices, and Amazon Fire TV. PokerGO is available worldwide except in China.
Service plans
PokerGO launched with a two-tier subscription model: monthly and annual. PokerGO is now on a three-tier subscription model: monthly, quarterly, and annual.
PokerGO Studio
PokerGo announced in April 2018 that they would be building a 10,000 square-foot PokerGO Studio at the ARIA Resort & Casino. The studio has space for nine poker tables and a capacity of up to 300 people. It includes space for fans and spectators, a full-service bar, a lounge for seating, and the flexibility to host a wide variety of events.
The PokerGO Studio opened in May 2018 with the filming of Poker After Dark. Open House week featured two nights of $100/$200 No-Limit Hold’em cash games with players including Daniel Negreanu, Maria Ho, Brandon Adams, Eli Elezra, Bill Perkins, Dan Shak, Mike Matusow, Matt Berkey, Tom Marchese, Antonio Esfandiari, and Phil Hellmuth.
The first tournament series at the PokerGO Studio was held later that month with the 2018 Super High Roller Bowl attracting 48 players. Justin Bonomo defeated Daniel Negreanu heads-up to win the $5,000,000 first-place prize and his second Super High Roller Bowl title.
Poker
The PokerGO Studio is the home for PokerGO-owned live events from poker tournaments to cash games.
The Super High Roller Bowl, U.S. Poker Open, and Poker Masters tournament series' have been held inside the PokerGO Studio since 2018, and new PokerGO shows of High Stakes Duel and High Stakes Feud were filmed in the PokerGO Studio. It has also hosted World Poker Tour final tables including the WPT Bobby Baldwin Classic and WPT Five Diamond World Poker Classic.
The PokerGO Studio also hosts cash games including Poker After Dark, High Stakes Poker, Friday Night Poker, Dolly's Game, and Rob's Home Game. Poker After Dark originally filmed at South Point Casino, Golden Nugget, and ARIA Resort & Casino, before relocating to the PokerGO Studio during Season 9. High Stakes Poker originally filmed at the Golden Nugget, The Palms, South Point Casino, and the Bellagio Resort & Casino, before relocating to the PokerGO Studio when the show relaunched for Season 8 after a nearly 10-year hiatus.
Other poker events held from inside the PokerGO Studio include the Global Poker Awards.
References
Streaming media systems
Gambling in the United States
Internet streaming services
Poker companies
2017 establishments in Nevada
Companies based in Las Vegas
Entertainment companies established in 2017
Internet television streaming services
Subscription video on demand services | PokerGO | [
"Technology"
] | 1,937 | [
"Streaming media systems",
"Telecommunications systems",
"Computer systems"
] |
65,253,869 | https://en.wikipedia.org/wiki/New%20Towns%20for%20Old | "New Towns for Old" is a 1942 British promotional short film promoting the clearance of old historic "slum towns" and replacement with "new towns". It promotes the then new concept of town planning. It was directed by John Eldridge and scripted by the poet Dylan Thomas. The film was produced by the Ministry of Information and was one of the few wartime documentary to focus on a topic unrelated to the war.
The title alludes to a line from Aladdin: New Lamps for Old.
Synopsis
Two civil servants wander around various vantage points looking at the fictional town of Smokedale. One with a bowler hat and carrying an umbrella has a refined London accent; the other in a trilby and smoking a pipe has a Yorkshire accent.
The footage itself is largely in and around Sheffield and Manchester and the civic functions discussed are in Manchester Town Hall. They proudly look at the new housing completed so far.
The film discusses true figures from the replanning of the Manchester slums from 1922 onward: 26,000 condemned; 14,000 demolished (plus "some help from Hitler"); 30,000 new houses planned. It stresses the need for a Green Belt around each town. Schools, hospitals and play areas are to be part of the plan. Old industries are discussed (and were in truth the hardest issue to address). The solution for relocating industries is not fully explained, and simply states that new areas will be zoned for industrial use - away from the housing.
It explains how war has delayed the plan.
It states "we've got to rebuild all our big towns".
The men then point to the camera and address the viewer, saying it is up to You. Remember it's your town.
Later Recognition
The title was repeated in the 1962 guide to town planning "New Towns for Old" by J. B. Cullingworth.
References
External links
New Towns for Old at Screenonline
1942 films
British short documentary films
Urban planning
Films directed by John Eldridge
1940s British films | New Towns for Old | [
"Engineering"
] | 406 | [
"Urban planning",
"Architecture"
] |
65,253,881 | https://en.wikipedia.org/wiki/Laura%20Fabris | Laura Fabris is a professor at Polytechnic University of Turin, formerly associate professor for materials science and engineering at Rutgers University, New Jersey, United States.
Life
Fabris studied chemistry at the University of Padua and finished her master's studies with her master's thesis "Artificial Photosynthetic Reaction Centers: Paramagnetic Intermediates Detected by EPR Spectroscopy" in 2001. She then received her doctoral degree in chemical sciences in April 2006 from the same university. The title of her dissertation was "Peptide Monolayers on Gold Nanoparticles and Surfaces". From 2006 to 2009, she was then a postdoc at the University of California, Santa Barbara. In March 2009, she was also a visiting researcher at the National University of Singapore. In July 2009, she became assistant professor in the Department of Materials Science and Engineering at Rutgers University. From June to August 2011, she was a visiting professor in the Air Force Research Laboratory. In July 2016, she is an associate professor at Rutgers University. She is now a full professor at Polytechnic University of Turin in the Department of Applied Science and Technology.
Awards
She received an Air Force Summer Faculty Fellowship in 2011 and the Rutgers Faculty Research Award in 2012.
Research
Fabris research concentrates on plasmonic nanoparticles and their synthesis, functionalization, characterization and application. She is also an expert in surface enhanced Raman scattering (SERS).
References
External links
Living people
Rutgers University faculty
University of Padua alumni
Italian materials scientists
Women materials scientists and engineers
Year of birth missing (living people) | Laura Fabris | [
"Materials_science",
"Technology"
] | 319 | [
"Women materials scientists and engineers",
"Materials scientists and engineers",
"Women in science and technology"
] |
65,254,591 | https://en.wikipedia.org/wiki/Guillermo%20Rein | Guillermo Rein (born May 1975) is a professor of fire science in the Department of Mechanical Engineering at Imperial College London. His research is focused on fire, combustion, and heat transfer. He is the editor-in-chief of the journal Fire Technology and Fellow of the Combustion Institute.
Rein is best known for his contributions to smouldering combustion research in the field of fire science.
Biography
Rein obtained his Industrial Engineering degree at the ICAI School of Engineering in 1999. He studied mechanical engineering at the University of California, Berkeley, and obtained an MSc in 2003 and a PhD. in 2005. He taught at the School of Engineering of the University of Edinburgh (2006–2012), where he was a senior lecturer before moving to Imperial College in 2012.
Research
His research meanly focus on heat transfer, combustion, fire and wildfire. He is best known in three areas: polymer and wood ignition; design of fire-resistant structures; and wildfire spread and mitigation.
Rein, together with his research group and collaborators, has edited two books, published six book chapters and over 200 journal publications. His current h-index is above 60 and citation count is over 12,000 on Google Scholar.
Rein has been editor-in-chief of the journal Fire Technology since 2012. He was associate editor of Proceedings of the Combustion Institute from 2013 to 2019; associate editor of Thermal and Mass Transport (Frontiers of Mechanical Engineering) from 2016; and is on the editorial board of Safety Science and the advisory board of International Journal of Wildland Fire since 2016. He was also on the editorial board of Fire Safety Journal from 2014 to 2017.
Selected awards
2009 Hinshelwood Prize
2016 SFPE Lund Award
2017 The Engineer Collaborate-to-Innovate Prize
2017 Sugden Award
2018 Arthur B. Guise Medal
2020 Research Excellence Award
References
External links
Imperial Hazelab's webpage
Mechanical engineers
Living people
University of California, Berkeley alumni
Academics of Imperial College London
Combustion engineering
Fellows of the Combustion Institute
Academics of the University of Edinburgh
Fire
Science communicators
21st-century British scientists
21st-century Spanish scientists
21st-century British educators
21st-century British engineers
1975 births | Guillermo Rein | [
"Chemistry",
"Engineering"
] | 436 | [
"Mechanical engineers",
"Combustion engineering",
"Industrial engineering",
"Fellows of the Combustion Institute",
"Combustion",
"Mechanical engineering",
"Fire"
] |
65,254,959 | https://en.wikipedia.org/wiki/Homemade%20firearm | A homemade firearm, also called a ghost gun or privately made firearm, is a firearm made by a private individual, in contrast to one produced by a corporate or government entity. The term ghost gun is used mostly in the United States by gun control advocates, but it is being adopted by gun rights advocates and the firearm industry.
Production
United States
Under U.S. federal law, the creation of a firearm for non-commercial purposes (i.e., personal use) has, almost without exception, been unlicensed and legal. Since the passage of the Gun Control Act of 1968, however, anyone intending to manufacture firearms for sale or distribution is required to obtain a Federal Firearms License, and each firearm made is required to bear a unique serial number.
In 2022, the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF) issued a rule that determined "buy build shoot" kits, which can be assembled into functioning firearms in as little as 20 minutes, fit within the definition of "frame or receiver" used in the Gun Control Act of 1968. The ATF regulation, Final Rule 2021-05F, went into effect on August 24, 2022. This regulation expanded upon the current terms used in the Code of Federal Regulations by addition of the following:
The ATF rule thus required such kits to have serial numbers, required manufacturers of such kits to be licensed, and required commercial sellers of such kits to conduct background checks for purchasers. Under U.S. law, the frame or receiver of a firearm is treated as though it were a firearm itself; accordingly, both are subject to similar regulations.
The rule was challenged in court by gun advocacy groups, and a U.S. district judge in Texas, Reed O'Connor, ruled in 2023 that the ATF rule exceeded the agency's authority and issued a nationwide injunction blocking the rule. However, the U.S. has appealed to the Fifth Circuit, and O'Connor's injunction was stayed by the U.S. Supreme Court, allowing the rule to go into effect pending further proceedings.
While some states have passed laws restricting the creation of homemade firearms, in most states unfinished receivers are sold without requiring a federal or state background check.
History
Most receiver blanks from the 20th century could be finished with hand tools, a drill press, or machine tools. Certain companies in the 1990s began to sell receiver kits that could include drill bits, stencils, or jigs to aid the finishing process.
Starting in the 2010s, polymer receiver blanks and kits became popular, which require only hand tools for finishing. Polymer80, based in Dayton, Nevada, became well known for being a top producer of such receivers.
It has always been possible to make firearms from raw materials, and more recently it has become popular among firearms hobbyists to produce receivers from plastic with a 3D printer, though the variety of materials and methods used to create these receivers are of varying quality.
A popular machine tool for completing receiver blanks is a CNC mill. The company Defense Distributed sells a CNC milling machine named the Ghost Gunner for this purpose. The Ghost Gunner was first sold in 2014, when the term "ghost gun" became popularized.
AR-15-style firearms are often made as homemade firearms. AR-15s are modular firearms, and maker's marks are usually applied to the lower receiver, which houses the trigger group. A person with an AR-15 lower receiver can assemble a complete firearm using widely available, commercial and unregulated components, such as barrels, stocks, and upper receivers.
Pistols and AK-47-style semi-automatic rifles are also popularly made as homemade firearms. The Intelligence Division of the New York City Police Department has published a survey and compendium of homemade firearm types.
Non-U.S. jurisdictions
Overseas production centers of clandestine homemade firearms include China, the Khyber Pass area of Pakistan, and the Philippines; the Philippines are especially known for the production of .45 caliber semi-automatic pistols.
Political controversy
Traceability
Because they lack serial numbers and manufacturer identification, homemade firearms are more difficult to trace than conventional firearms.
To help trace homemade firearms used in crime and assist detectives in criminal investigations, ATF officials have advised law enforcement agencies to submit evidence obtained in investigations to the National Integrated Ballistic Information Network (NIBIN).
In a 2021 commentary on firearms in the journal Injury Epidemiology, firearm violence expert Garen Wintemute wrote that "The potential for large-scale, clandestine firearm manufacture in support of armed extremist groups is cause for great concern." Wintemute wrote that the relative inexpensiveness of 3D-printing equipment could facilitate the growths of arsenals held by violent extremist organizations. Mexican drug cartels are reported to be developing 3D-printed grenade launchers.
While there are no reliable statistics on how many homemade firearms are being recovered in crimes, since the issue rose to prominence in California, the ATF has documented recoveries of homemade firearms in 38 States plus DC, Puerto Rico, and the Virgin Islands. The ATF noted an increasing number of homemade firearm seizures every year since 2016, and over 1,600 of these firearms have been entered into NIBIN.
Advocates
Gun rights activists support the private production of firearms, claiming the practice as a constitutional right and a way to maintain the privacy of gun owners. Individuals have organized "build parties" where equipment and expertise are shared to help create homemade firearms. Advocates say that homemade firearms are rarely used in crime despite widespread ownership. Gun rights advocates and law enforcement assert that because of the cost and effort required to make homemade firearms, criminals would prefer to steal firearms for use in crime, a fact borne out by DOJ statistics. While the ATF does not track homemade firearms, the FBI reports that their use in crimes is increasing.
Notable crimes
Noted crimes in which homemade firearms were used include the shooting sprees in Rancho Tehama, California (2017), Baltimore, Maryland (2017), and Kingsessing, Philadelphia (2023). In each of these cases, the shooter used home-assembled AR-15–style rifles. Recently, law enforcement officials in the United States have begun encountering privately made machine gun conversion devices. Devices such as the Glock switch have been used in crimes such as the 2022 Sacramento shooting. In December 2024, UnitedHealthcare CEO Brian Thompson was fatally shot by a partially 3D-printed Glock 19 and 3D-printed suppressor.
On July 8, 2022, former Japanese prime minister Shinzo Abe was assassinated in Nara, Japan, using a homemade "zip-gun" that was electrically fired via a metal filament wire heating up near the propellant.
U.S. law
U.S. federal law
Congress passed the Gun Control Act of 1968 or the GCA, to expand interstate commerce controls over common firearms like handguns, shotguns and rifles. The GCA requires those who are "engaged in the business" of manufacturing or dealing in firearms to be licensed by the ATF. Federal firearms licensees are required to mark their firearms' serial numbers and keep records of their transactions. The GCA also prohibits certain categories of persons, like convicted felons, domestic abusers, current users of illicit drugs and others, from possessing firearms.
To help enforce these prohibitions, Congress passed the Brady Act in 1993, creating the National Instant Criminal Background Check System, or NICS, and requiring FFLs to submit potential firearms purchaser information to NICS before transferring firearms.
While Congress passed the GCA as a response to the assassination of then-President John F. Kennedy, its drafters expressly added that the Act was not intended to place any undue burden on law-abiding citizens who use or make firearms for lawful, private purposes.
ATF enforcement and discretion
The ATF's involvement in regulating homemade firearms is primarily through its regulation of the receiver blanks commonly used to create such firearms. The ATF has exerted enforcement discretion in determining when it believes a receiver blank meets the statutory definition of a frame or receiver under the Gun Control Act of 1968. If a receiver blank is believed to be a frame or receiver, it is treated by ATF as a firearm and subjected to certain controls. The following graphic illustrates the features ATF considers preclude a receiver blank from regulation as a frame or receiver:
Conversely, a receiver blank with the following features is considered by the agency to be a receiver subject to control as a 'firearm' under the Gun Control Act of 1968:
U.S. state laws
California
In 2014, the California Legislature passed a bill to require serial numbers on receiver blanks and all other firearms, including antique guns, but it was vetoed by Governor Jerry Brown. However, in 2016, it passed a measure requiring anyone planning to build a homemade firearm to obtain a serial number from the state (de facto registration) and pass a background check. From July 1, 2024, "firearm precursor parts" may only be sold through a licensed dealer.
Colorado
On January 4, 2022, Mayor Michael B. Hancock signed into law a bill outlawing certain homemade firearms in Denver, Colorado. The law outlaws the creation, carriage, transportation, discharge, and sale of firearms without serial numbers.
On June 2, 2023, Governor Jared Polis signed Senate Bill 23-279 (Unserialized Firearms And Firearm Components) into law. The law bans the manufacture, possession and sale of unserialized firearms and unserialized frames/receivers, effective January 1, 2024. A violation is made a Class 1 misdemeanor, and a subsequent offense is a Class 5 felony. It also provides regulations requiring existing unserialized firearms to be serialized by a licensed firearms dealer (and for the owners to have background checks) by January 1, 2024.
Connecticut
Since October 1, 2019, all manufactured guns must have a serial number obtained from the Department of Emergency Services and Public Protection engraved. Any plastic gun that "after removal of grips, stocks and magazines, is not ... detectible" by metal detectors is banned under Connecticut law.
Delaware
On October 20, 2021, Governor John Carney signed House Bill 125 into law, which "establishes the crimes of possession of an unfinished firearm frame or receiver with no serial number, possession of and manufacturing a covert or undetectable firearm, possession of and manufacturing an untraceable firearm, and manufacturing or distributing a firearm using a three-dimensional printer." The bill effectively prohibits private manufacture of a firearm, by criminalizing possession of an untraceable firearm, including unfinished frames and receivers.
The Delaware law is being challenged in litigation by gun-rights activists, specifically the Firearms Policy Coalition and two individuals. In September 2022, in the case of Rigby v. Jennings, Federal District Court Judge Maryellen Noreika issued a preliminary injunction that barred Delaware from enforcing the portion of the law that restricts the possession and manufacture of untraceable firearms, siding with plaintiffs on their claim that they were likely to succeed on the merits of their Second Amendment claim. However, Noreika denied the plaintiffs' request for an injunction to block the parts of the law that regulate firearm distribution and prohibit distribution of computer code that would facilitate the manufacture of 3D-printed guns.
Illinois
With the signing of HB4383 in May 2022, building, selling, or possessing homemade firearms without serial numbers is prohibited in Illinois.
Maryland
In 2022 Maryland governor Larry Hogan allowed legislation that will, according to The Washington Post, "ban the sale, receipt and transfer of unfinished frames or receivers that are not serialized by the manufacturer" to become law without his signature. This law will also outlaw the mere possession of such items starting in March 2023.
New Jersey
S2465, enacted in November 2018, prohibits the manufacture and sale of guns or parts that are or can become a homemade firearm. Multiple arrests were made within months of this law going into effect. Then State Attorney General Gurbir Grewal aggressively prosecuted infractions of this law. New Jersey filed a lawsuit against U.S. Patriot Armory, a company that allegedly sold AR-15 build kits to New Jersey residents. In July 2019, S3897 was enacted, which criminalizes transferring or possessing unserialized firearms.
New York
In 2015, during the state of New York's first prosecution for sale of homemade firearms, Then State Attorney General Eric Schneiderman said that it was "easy" for "criminals to make completely untraceable, military-grade firearms." In 2019, New York passed a law to prohibit the making, selling, transporting or possessing 3D-printed guns or other undetectable firearms.
On October 28, 2021, New York Governor Kathy Hochul signed into law restrictions on homemade firearms. This consisted of The Scott J. Beigel Unfinished Receiver Act and The Jose Webster Untraceable Firearms Act.
Pennsylvania
In December 2019 Josh Shapiro, then Attorney General, issued a legal opinion that 80% lower receivers are considered firearms. After a legal challenge, in January 2020 the Commonwealth Court issued a preliminary injunction blocking AG Shapiro's opinion. A bill passed by the Pennsylvania House of Representatives in 2024 would make it a third-degree felony to sell or transfer firearm parts without serial numbers. The bill has not been passed by the Pennsylvania Senate.
Pending legislation
United States Congress
On July 1, 2020, Representatives Jamie Raskin (MD-08) and David Cicilline (RI-01) introduced House Resolution 7468, aiming to outlaw certain conduct in relation to homemade firearms. As of September 22, 2020, the most recent action taken on the bill was on July 1, when it was referred to the House Committee on the Judiciary.
Massachusetts
As of April 2020, there are at least two bills that aim to control the distribution of firearm kits as well as 3D printed firearms in the Commonwealth: Bill H.3843, "An Act relative to ghost guns", presented by Marjorie C. Decker of 25th Middlesex district, and Bill S.2649, "An Act relative to 3D printed firearm and ghost guns", presented by Michael J. Barrett of 3rd Middlesex district. Both bills have been deferred to the Committee of Ways and Means in the Senate and House, respectively.
Illinois
On February 7, 2019, Illinois House Rep. Kathleen Willis filed HB2253, entitled the Undetectable and Untraceable Firearms Act, with the Clerk of the House was the Bill was announced to the House. It was then referred to the House Rules Committee for assignment to a substantive committee, and to be formally heard by lawmakers and the public. The Untraceable Firearms Act, for short, proposes to amend the Firearm Owners Identification Card Act primarily by prohibiting the possession, manufacturing, and distribution of "unfinished frames or receivers" without having a FOID (Firearm Owners Identification Card) in his or her possession, among other requirements. HB2253 also proposes to include homemade firearms as a new class of prohibited firearm in certain areas, including public buildings. Violations of HB2253 would result in the commission of a Class 2 felony, punishable by 3 to 7 years in the Illinois Department of Corrections and fines up to $25,000.
The Bill has garnered both support and criticism among lawmakers. In the Bill's introduction, Rep. Willis stated, "I'm not calling for a ban on them, I'm just saying that you need to have the same background checks as you would if you were going to purchase a regular gun..." On the other hand, the Federal Firearms Licensees of Illinois have voiced 2nd Amendment concerns on behalf of gun sellers: "[Rep. Willis is] trying to make it illegal for the home hobbyist to own or possess firearms they've made. They're going after an industry and a hobby and lawful gun owners."
See also
Improvised firearm
List of 3D-printed weapons and parts
Right to keep and bear arms
Notes
References
External Links
Ghostguns.com
DEFCAD.com
2023 NYPD Intelligence Brief on Ghost Guns
Firearm construction
Gun politics in the United States | Homemade firearm | [
"Engineering"
] | 3,287 | [
"Firearm construction",
"Mechanical engineering"
] |
65,257,148 | https://en.wikipedia.org/wiki/MicMac%20%28software%29 | MicMac is an open-source software for photogrammetry developed by the French National Geographic Institute.
See also
Comparison of photogrammetry software
References
External links
Official website
Citations of Rupnik et al. (2017).
Photogrammetry software
Free and open-source software | MicMac (software) | [
"Technology"
] | 57 | [
"Computing stubs",
"Software stubs"
] |
66,478,927 | https://en.wikipedia.org/wiki/Aleksandar%20Kav%C4%8Di%C4%87 | Aleksandar Kavčić (; born 1968 in Belgrade) is a Serbian electrical engineer, university professor and philanthropist who is currently active as an Adjunct Professor of Electrical Engineering at the Carnegie Mellon University since 2017 and as a Professor of Electrical Engineering at the University of Hawai'i at Manoa.
Biography
He studied at the prestigious Mathematical Grammar School and University of Belgrade School of Electrical Engineering. After completing his studies, Kavčić moved abroad due to the civil war which took place in former Yugoslavia.
Prior to 2017, Kavčić served as assistant professor, associate professor and professor of electrical engineering at Harvard University and the University of Hawai'i at Manoa where he is presently Professor of Electrical Engineering. He also served as visiting associate professor at the City University of Hong Kong in the Fall of 2005 and as visiting scholar at the Chinese University of Hong Kong in the Spring of 2006.
In 2016, the Carnegie Mellon University won a lawsuit against the Marvell Technology Group for infringing intellectual property of Kavčić and his mentor Jose Moura, gaining a settlement of US$750,000,000.
He is the founder of "Alek Kavčić Foundation" which has the goal to provide high-quality textbooks available for free download for all elementary school students in Serbia. Over the years, he donated new computers to a number of high schools in Serbia.
Kavčić resides in Austin and Belgrade.
Political career
In the 2020 Serbian parliamentary elections, he was a candidate for MP on the electoral list of the Enough is Enough (DJB) party, and Kavčić was presented as the president of the party education board. The party failed to pass the electoral threshold, and Kavčić decided to leave the party.
Selected works
The Viterbi algorithm and Markov noise memory, co-author, 2000
Binary intersymbol interference channels: Gallager codes, density evolution, and code performance bounds, co-author, 2003
Equal-diagonal QR decomposition and its application to precoder design for successive-cancellation detection, co-author, 2005
Simulation-based computation of information rates for channels with memory, co-author, 2006
The feasibility of magnetic recording at 10 terabits per square inch on conventional media, co-author, 2009
References
External links
An interview with Kavčić
1968 births
People from Belgrade
Ruhr University Bochum alumni
Living people
21st-century Serbian engineers
Electrical engineers
Serbian academics
Carnegie Mellon University faculty
University of Hawaiʻi at Mānoa faculty
Harvard University faculty
Enough is Enough (party) politicians | Aleksandar Kavčić | [
"Engineering"
] | 513 | [
"Electrical engineering",
"Electrical engineers"
] |
66,479,322 | https://en.wikipedia.org/wiki/Protein%20carbonylation | In biochemistry, protein carbonylation refers to oxidation of the side chains of proteins to introduce ketone () and aldehyde () groups in a protein. The following amino acid residues are affected:
prolyl to pyrrolidone
glutamyl to glutamic semialdehyde
lysyl to aminoadipic acid semialdehyde
threonyl to amino ketobutyric acid
Carbonylation is typically assumed to be the result of reactive oxygen species (ROS) attacking the protein side chain. ROS species include hydroperoxide or lipic hydroperoxides. Protein carbonylation is of interest because of its association with various diseases. Oxidative stress, often metal catalyzed, leads to protein carbonylation.
References
Reactive oxygen species
Post-translational modification | Protein carbonylation | [
"Chemistry"
] | 170 | [
"Post-translational modification",
"Gene expression",
"Biochemical reactions"
] |
66,479,755 | https://en.wikipedia.org/wiki/Grammatophora%20%28alga%29 | Grammatophora is a genus of Chromista belonging to the family Grammatophoraceae.
The genus was first described by C. G. Ehrenberg in 1840.
Species:
Grammatophora marina
Grammatophora oceanica
References
Diatoms
Diatom genera | Grammatophora (alga) | [
"Biology"
] | 59 | [
"Diatoms",
"Algae"
] |
66,481,715 | https://en.wikipedia.org/wiki/Earth%20auger | An earth auger, earth drill, or post-hole auger is a drilling tool used for making holes in the ground. It typically consists of a rotating vertical metal rod or pipe with one or more blades attached at the lower end, that cut or scrape the soil.
History
Metal augers have been in use since the Middle Ages to drill holes in wood. In the 19th century, the hand-operated earth auger became a common farm and construction tool in the US, and several inventors submitted patents for them. An example is the design of a certain M. Hubby of Maysfield, Texas, consisting of an open hollow cylinder with two blades at the bottom edge.
The first known power earth auger was built in 1943 by John Habluetzel, a farmer in Wamego, Kansas, from parts scavenged from other equipment, including a 7-inch helical blade from a screw separator. It was attached to a tractor and could be operated by the driver from his seat. It dug one 2.5 foot deep hole every minute. His invention was featured in the Kansas State Board of Agriculture's 35th Biennial Report. He went on to dig holes for other farmers at 10 cents per hole, a side business that he operated well into the 1950s. He donated his invention to the Kansas Museum of History in 1999.
Types
Blade arrangement
The most common design of earth auger has a helical screw blade (the flighting) winding around lower part of the shaft. The lower edge of the screw blade scrapes dirt at the bottom of the hole, and the rest of the blade acts like a screw conveyor to lift the loose soil out of the way. When the hole reaches the desired depth and the tool is pulled out, the screw blade scoops out the remaining loose dirt.
The rod may end in a sharp point protruding below the screw blade. Its purpose is to push the dirt that lies just below the rod to the sides, where the blade can pick it up. It also helps keep the hole straight by prevent the auger from wandering off to the side. The lower edge of the screw blade may have teeth.
Another type of earth auger has two vertical blades instead of a helical screw. Rather than scraping the soil at the bottom of the hole, this type of auger cuts a cylindrical plug out of it, that is held by friction between the two blades. The auger must then be pulled out and emptied every foot or so. This type may require less force to operate, but may be adequate only for certain types of soil.
Power source
An earth auger can be powered by hand, through a T-shaped horizontal handle at the top of the rod.
An earth auger can also be powered by an electric motor or internal-combustion engine, or from a tractor or other vehicle through a power take-off.
Uses
Hand-powered earth augers are typically used to plant saplings and trees or to set up posts for fences or other ends.
Large mechanized earth augers, called drilling rigs, are used to make holes for piles destined to be deep foundations or retaining wall.
Gas- or hand-powered augers are used by ice fishermen to drill through the ice layer over lakes or rivers.
See also
Oil drilling
Wood auger
Post hole digger
References
Agricultural machinery
Gardening tools
Mechanical hand tools | Earth auger | [
"Physics"
] | 682 | [
"Mechanics",
"Mechanical hand tools"
] |
66,482,576 | https://en.wikipedia.org/wiki/Corey%E2%80%93Nicolaou%20macrolactonization | Corey–Nicolaou macrolactonization is a named reaction of organic chemistry, for the synthesis of lactones from hydroxy acids, found in 1974. The reaction uses 2,2'-dipyridyldisulfide and triphenylphosphine as reagents and runs in polar aprotic solvent under mild conditions.
Mechanism
The hydroxy acid first reacts with the 2,2'-Dipyridyldisulfide to form the corresponding 2-pyridinethiol ester, and after a proton transfer, the alkoxide attacks the carbonyl carbon, forming a tetrahedral transition state, before resolving back to the desired lactone and 2-pyridinethione.
Variants
Other heterocyclic disulfides have been used in place of 2,2'-dipyridyldisulfide.
See also
Shiina macrolactonization
Ružička reaction
References | Corey–Nicolaou macrolactonization | [
"Chemistry"
] | 191 | [
"Name reactions"
] |
66,482,899 | https://en.wikipedia.org/wiki/Mirrors%20and%20Reflections | Mirrors and Reflections: The Geometry of Finite Reflection Groups is an undergraduate-level textbook on the geometry of reflection groups. It was written by Alexandre V. Borovik and Anna Borovik and published in 2009 by Springer in their Universitext book series. The Basic Library List Committee of the Mathematical Association of America has recommended its inclusion in undergraduate mathematics libraries.
Topics
Mirrors and Reflections is divided into five major parts, with two appendices. The first part provides background material in affine geometric spaces, geometric transformations,, arrangements of hyperplanes,, and polyhedral cones. The second part introduces the definitions of reflection systems and reflection groups, the special case of dihedral groups, and root systems.
Part III of the book concerns Coxeter complexes, and uses them as the basis for some group theory of reflection groups, including their length functions and parabolic subgroups. Part IV, "the highlight in this book", proves the classification of finite reflection groups and of root systems. The final part of the book studies in more detail and through more elementary methods the three-dimensional finite reflection groups and the symmetries of the regular icosahedron. Appendices provide suggestions for mathematical visualization, and list hints and solutions for exercises.
Audience and reception
Mirrors and Reflections is aimed at undergraduate mathematics students, and uses an intuitive and heavily visual approach suitable for that level. its readers are expected to already have a solid background in linear algebra and some group theory. Reviewer Gizem Karaali recommends the book, both as a textbook for a "capstone" undergraduate course, and as individual reading for students interested in this topic.
Related works
There are several other standard textbooks on reflection groups, including Groupes et algèbres de Lie, Chapitres 4, 5 et 6 (Bourbaki, 1968), Finite Reflection Groups (L. C. Grove and C. T. Benson, 1985), and Reflection Groups and Coxeter Groups (James E. Humphreys, 1990). However, these take a more algebraic and less geometric view of the subject than Mirrors and Reflections, and are less accessible to undergraduates.
References
Mathematics textbooks
2009 non-fiction books
Reflection groups | Mirrors and Reflections | [
"Physics"
] | 442 | [
"Euclidean symmetries",
"Reflection groups",
"Symmetry"
] |
66,483,113 | https://en.wikipedia.org/wiki/Guinardia | Guinardia is a genus of diatoms belonging to the family Rhizosoleniaceae.
The genus was first described by H. Peragallo in 1892.
The genus has cosmopolitan distribution.
Species:
Guinardia delicatula
Guinardia flaccida
Guinardia pungens
Guinardia striata
References
Diatoms
Diatom genera | Guinardia | [
"Biology"
] | 76 | [
"Diatoms",
"Algae"
] |
66,483,338 | https://en.wikipedia.org/wiki/Halamphora | Halamphora is a genus of diatoms belonging to the family Amphipleuraceae.
The genus was first described by C. Mereschkowsky in 1903.
The genus has cosmopolitan distribution.
Species:
Halamphora coffeaeformis
Halamphora hybrida
References
Diatoms
Diatom genera | Halamphora | [
"Biology"
] | 65 | [
"Diatoms",
"Algae"
] |
66,486,540 | https://en.wikipedia.org/wiki/May%202170%20lunar%20eclipse | A total lunar eclipse will occur at the Moon’s descending node of orbit on Wednesday, May 30, 2170, with an umbral magnitude of 1.7488. It will be a central lunar eclipse, in which part of the Moon will pass through the center of the Earth's shadow. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A total lunar eclipse occurs when the Moon's near side entirely passes into the Earth's umbral shadow. Unlike a solar eclipse, which can only be viewed from a relatively small area of the world, a lunar eclipse may be viewed from anywhere on the night side of Earth. A total lunar eclipse can last up to nearly two hours, while a total solar eclipse lasts only a few minutes at any given place, because the Moon's shadow is smaller. Occurring about 3.6 days after perigee (on May 26, 2170, at 10:15 UTC), the Moon's apparent diameter will be larger.
This will be the greatest lunar eclipse of Lunar Saros 133 as well as the largest and darkest lunar eclipse of the 22nd century.
Visibility
The eclipse will be completely visible over central and eastern South America, western Europe, and much of Africa, seen rising over western South America and much of North America and setting over eastern Europe, the western half of Asia, and western Australia.
Eclipse details
Shown below is a table displaying details about this particular solar eclipse. It describes various parameters pertaining to this eclipse.
Eclipse season
This eclipse is part of an eclipse season, a period, roughly every six months, when eclipses occur. Only two (or occasionally three) eclipse seasons occur each year, and each season lasts about 35 days and repeats just short of six months (173 days) later; thus two full eclipse seasons always occur each year. Either two or three eclipses happen each eclipse season. In the sequence below, each eclipse is separated by a fortnight. The first and last eclipse in this sequence is separated by one synodic month.
Related eclipses
Eclipses in 2170
A partial solar eclipse on May 16.
A total lunar eclipse on May 30.
A partial solar eclipse on June 14.
A partial solar eclipse on November 8.
A total lunar eclipse on November 23.
A partial solar eclipse on December 7.
Metonic
Preceded by: Lunar eclipse of August 11, 2166
Followed by: Lunar eclipse of March 18, 2174
Tzolkinex
Preceded by: Lunar eclipse of April 19, 2163
Followed by: Lunar eclipse of July 11, 2177
Half-Saros
Preceded by: Solar eclipse of May 25, 2161
Followed by: Solar eclipse of June 5, 2179
Tritos
Preceded by: Lunar eclipse of June 30, 2159
Followed by: Lunar eclipse of April 29, 2181
Lunar Saros 133
Preceded by: Lunar eclipse of May 18, 2152
Followed by: Lunar eclipse of June 9, 2188
Inex
Preceded by: Lunar eclipse of June 19, 2141
Followed by: Lunar eclipse of May 10, 2199
Triad
Preceded by: Lunar eclipse of July 29, 2083
Followed by: Lunar eclipse of March 30, 2257
Lunar eclipses of 2168–2172
This eclipse is a member of a semester series. An eclipse in a semester series of lunar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternating nodes of the Moon's orbit.
The lunar eclipses on January 24, 2168 (partial), July 20, 2168 (penumbral), and January 13, 2169 (penumbral) occur in the previous lunar year eclipse set, and the penumbral lunar eclipses on April 9, 2172 and October 2, 2172 occur in the next lunar year eclipse set.
Saros 133
Tritos series
Half-Saros cycle
A lunar eclipse will be preceded and followed by solar eclipses by 9 years and 5.5 days (a half saros). This lunar eclipse is related to two annular solar eclipses of Solar Saros 140.
References
2170-05
2170-05
22nd-century lunar eclipses | May 2170 lunar eclipse | [
"Astronomy"
] | 849 | [
"Future astronomical events",
"Future lunar eclipses"
] |
66,487,331 | https://en.wikipedia.org/wiki/Graph%20flattenability | Flattenability in some -dimensional normed vector space is a property of graphs which states that any embedding, or drawing, of the graph in some high dimension can be "flattened" down to live in -dimensions, such that the distances between pairs of points connected by edges are preserved. A graph is -flattenable if every distance constraint system (DCS) with as its constraint graph has a -dimensional framework. Flattenability was first called realizability, but the name was changed to avoid confusion with a graph having some DCS with a -dimensional framework.
Flattenability has connections to structural rigidity, tensegrities, Cayley configuration spaces, and a variant of the graph realization problem.
Definitions
A distance constraint system , where is a graph and is an assignment of distances onto the edges of , is -flattenable in some normed vector space if there exists a framework of in -dimensions.
A graph is -flattenable in if every distance constraint system with as its constraint graph is -flattenable.
Flattenability can also be defined in terms of Cayley configuration spaces; see connection to Cayley configuration spaces below.
Properties
Closure under subgraphs. Flattenability is closed under taking subgraphs. To see this, observe that for some graph , all possible embeddings of a subgraph of are contained in the set of all embeddings of .
Minor-closed. Flattenability is a minor-closed property by a similar argument as above.
Flattening dimension. The flattening dimension of a flattenable graph in some normed vector space is the lowest dimension such that is -flattenable. The flattening dimension of a graph is closely related to its gram dimension. The following is an upper-bound on the flattening dimension of an arbitrary graph under the -norm.
Theorem. The flattening dimension of a graph under the -norm is at most .
For a detailed treatment of this topic, see Chapter 11.2 of Deza & Laurent.
Euclidean flattenability
This section concerns flattenability results in Euclidean space, where distance is measured using the norm, also called the Euclidean norm.
1-flattenable graphs
The following theorem is folklore and shows that the only forbidden minor for 1-flattenability is the complete graph .
Theorem. A graph is 1-flattenable if and only if it is a forest.
Proof. A proof can be found in Belk & Connelly. For one direction, a forest is a collection of trees, and any distance constraint system whose graph is a tree can be realized in 1-dimension. For the other direction, if a graph is not a forest, then it has the complete graph as a subgraph. Consider the DCS that assigns the distance 1 to the edges of the subgraph and the distance 0 to all other edges. This DCS has a realization in 2-dimensions as the 1-skeleton of a triangle, but it has no realization in 1-dimension.
This proof allowed for distances on edges to be 0, but the argument holds even when this is not allowed. See Belk & Connelly for a detailed explanation.
2-flattenable graphs
The following theorem is folklore and shows that the only forbidden minor for 2-flattenability is the complete graph .
Theorem. A graph is 2-flattenable if and only if it is a partial 2-tree.
Proof. A proof can be found in Belk & Connelly. For one direction, since flattenability is closed under taking subgraphs, it is sufficient to show that 2-trees are 2-flattenable. A 2-tree with vertices can be constructed recursively by taking a 2-tree with vertices and connecting a new vertex to the vertices of an existing edge. The base case is the . Proceed by induction on the number of vertices . When , consider any distance assignment on the edges . Note that if does not obey the triangle inequality, then this DCS does not have a realization in any dimension. Without loss of generality, place the first vertex at the origin and the second vertex along the x-axis such that is satisfied. The third vertex can be placed at an intersection of the circles with centers and and radii and respectively. This method of placement is called a ruler and compass construction. Hence, is 2-flattenable.
Now, assume a 2-tree with vertices is 2-flattenable. By definition, a 2-tree with vertices is a 2-tree with vertices, say , and an additional vertex connected to the vertices of an existing edge in . By the inductive hypothesis, is 2-flattenable. Finally, by a similar ruler and compass construction argument as in the base case, can be placed such that it lies in the plane. Thus, 2-trees are 2-flattenable by induction.
If a graph is not a partial 2-tree, then it contains as a minor. Assigning the distance of 1 to the edges of the minor and the distance of 0 to all other edges yields a DCS with a realization in 3-dimensions as the 1-skeleton of a tetrahedra. However, this DCS has no realization in 2-dimensions: when attempting to place the fourth vertex using a ruler and compass construction, the three circles defined by the fourth vertex do not all intersect.
Example. Consider the graph in figure 2. Adding the edge turns it into a 2-tree; hence, it is a partial 2-tree. Thus, it is 2-flattenable.
Example. The wheel graph contains as a minor. Thus, it is not 2-flattenable.
3-flattenable graphs
The class of 3-flattenable graphs strictly contains the class of partial 3-trees. More precisely, the forbidden minors for partial 3-trees are the complete graph , the 1-skeleton of the octahedron , , and , but , and are 3-flattenable. These graphs are shown in Figure 3. Furthermore, the following theorem from Belk & Connelly shows that the only forbidden minors for 3-flattenability are and .
Theorem. A graph is 3-flattenable if and only if it does not have or as a minor.
Proof Idea: The proof given in Belk & Connelly assumes that , and are 3-realizable. This is proven in the same article using mathematical tools from rigidity theory, specifically those concerning tensegrities. The complete graph is not 3-flattenable, and the same argument that shows is not 2-flattenable and is not 1-flattenable works here: assigning the distance 1 to the edges of yields a DCS with no realization in 3-dimensions. Figure 4 gives a visual proof that the graph is not 3-flattenable. Vertices 1, 2, and 3 form a degenerate triangle. For the edges between vertices 1- 5, edges and are assigned the distance and all other edges are assigned the distance 1. Vertices 1- 5 have unique placements in 3-dimensions, up to congruence. Vertex 6 has 2 possible placements in 3-dimensions: 1 on each side of the plane defined by vertices 1, 2, and 4. Hence, the edge has two distance values that can be realized in 3-dimensions. However, vertex 6 can revolve around the plane in 4-dimensions while satisfying all constraints, so the edge has infinitely many distance values that can only be realized in 4-dimensions or higher. Thus, is not 3-flattenable. The fact that these graphs are not 3-flattenable proves that any graph with either or as a minor is not 3-flattenable.
The other direction shows that if a graph does not have or as a minor, then can be constructed from partial 3-trees, , and via 1-sums, 2-sums, and 3-sums. These graphs are all 3-flattenable and these operations preserve 3-flattenability, so is 3-flattenable.
The techniques in this proof yield the following result from Belk & Connelly.
Theorem. Every 3-realizable graph is a subgraph of a graph that can be obtained by a sequence of 1-sums, 2-sums, and 3-sums of the graphs , , and .
Example. The previous theorem can be applied to show that the 1-skeleton of a cube is 3-flattenable. Start with the graph , which is the 1-skeleton of a tetrahedron. On each face of the tetrahedron, perform a 3-sum with another graph, i.e. glue two tetrahedra together on their faces. The resulting graph contains the cube as a subgraph and is 3-flattenable.
In higher dimensions
Giving a forbidden minor characterization of -flattenable graphs, for dimension , is an open problem. For any dimension , and the 1-skeleton of the -dimensional analogue of an octahedron are forbidden minors for -flattenability. It is conjectured that the number of forbidden minors for -flattenability grows asymptotically to the number of forbidden minors for partial -trees, and there are over forbidden minors for partial 4-trees.
An alternative characterization of -flattenable graphs relates flattenability to Cayley configuration spaces. See the section on the connection to Cayley configuration spaces.
Connection to the graph realization problem
Given a distance constraint system and a dimension , the graph realization problem asks for a -dimensional framework of the DCS, if one exists. There are algorithms to realize -flattenable graphs in -dimensions, for , that run in polynomial time in the size of the graph. For , realizing each tree in a forest in 1-dimension is trivial to accomplish in polynomial time. An algorithm for is mentioned in Belk & Connelly. For , the algorithm in So & Ye obtains a framework of a DCS using semidefinite programming techniques and then utilizes the "folding" method described in Belk to transform into a 3-dimensional framework.
Flattenability under p-norms
This section concerns flattenability results for graphs under general -norms, for .
Connection to algebraic geometry
Determining the flattenability of a graph under a general -norm can be accomplished using methods in algebraic geometry, as suggested in Belk & Connelly. The question of whether a graph is -flattenable is equivalent to determining if two semi-algebraic sets are equal. One algorithm to compare two semi-algebraic sets takes time.
Connection to Cayley configuration spaces
For general -norms, there is a close relationship between flattenability and Cayley configuration spaces. The following theorem and its corollary are found in Sitharam & Willoughby.
Theorem. A graph is -flattenable if and only if for every subgraph of resulting from removing a set of edges from and any -distance vector such that the DCS has a realization, the -dimensional Cayley configuration space of over is convex.
Corollary. A graph is not -flattenable if there exists some subgraph of and some -distance vector such that the -dimensional Cayley configuration space of over is not convex.
2-Flattenability under the l1 and l∞ norms
The and norms are equivalent up to rotating axes in 2-dimensions, so 2-flattenability results for either norm hold for both. This section uses the -norm. The complete graph is 2-flattenable under the -norm and is 3-flattenable, but not 2-flattenable. These facts contribute to the following results on 2-flattenability under the -norm found in Sitharam & Willoughby.
Observation. The set of 2-flattenable graphs under the -norm (and -norm) strictly contains the set of 2-flattenable graphs under the -norm.
Theorem. A 2-sum of 2-flattenable graphs is 2-flattenable if and only if at most one graph has a minor.
The fact that is 2-flattenable but is not has implications on the forbidden minor characterization for 2-flattenable graphs under the -norm. Specifically, the minors of could be forbidden minors for 2-flattenability. The following results explore these possibilities and give the complete set of forbidden minors.
Theorem. The banana graph, or with one edge removed, is not 2-flattenable.
Observation. The graph obtained by removing two edges that are incident to the same vertex from is 2-flattenable.
Observation. Connected graphs on 5 vertices with 7 edges are 2-flattenable.
The only minor of left is the wheel graph , and the following result shows that this is one of the forbidden minors.
Theorem. A graph is 2-flattenable under the - or -norm if and only if it does not have either of the following graphs as minors:
the wheel graph or
the graph obtained by taking the 2-sum of two copies of and removing the shared edge.
Connection to structural rigidity
This section relates flattenability to concepts in structural (combinatorial) rigidity theory, such as the rigidity matroid. The following results concern the -distance cone , i.e., the set of all -distance vectors that can be realized as a configuration of points in some dimension. A proof that this set is a cone can be found in Ball. The -stratum of this cone are the vectors that can be realized as a configuration of points in -dimensions. The projection of or onto the edges of a graph is the set of distance vectors that can be realized as the edge-lengths of some embedding of .
A generic property of a graph is one that almost all frameworks of distance constraint systems, whose graph is , have. A framework of a DCS under an -norm is a generic framework (with respect to -flattenability) if the following two conditions hold:
there is an open neighborhood of in the interior of the cone , and
the framework is -flattenable if and only if all frameworks in are -flattenable.
Condition (1) ensures that the neighborhood has full rank. In other words, has dimension equal to the flattening dimension of the complete graph under the -norm. See Kitson for a more detailed discussion of generic framework for -norms. The following results are found in Sitharam & Willoughby.
Theorem. A graph is -flattenable if and only if every generic framework of is -flattenable.
Theorem. -flattenability is not a generic property of graphs, even for the -norm.
Theorem. A generic -flattenable framework of a graph exists if and only if is independent in the generic -dimensional rigidity matroid.
Corollary. A graph is -flattenable only if is independent in the -dimensional rigidity matroid.
Theorem. For general -norms, a graph is
independent in the generic -dimensional rigidity matroid if and only if the projection of the -stratum onto the edges of has dimension equal to the number of edges of ;
maximally independent in the generic -dimensional rigidity matroid if and only if projecting the -stratum onto the edges of preserves its dimension and this dimension is equal to the number of edges of ;
rigid in -dimensions if and only if projecting the -stratum onto the edges of preserves its dimension;
not independent in the generic -dimensional rigidity matroid if and only if the dimension of the projection of the -stratum onto the edges of is strictly less than the minimum of the dimension of and the number of edges of .
References
Graphs
Graph theory | Graph flattenability | [
"Physics",
"Mathematics"
] | 3,223 | [
"Discrete mathematics",
"Mathematics of rigidity",
"Graph theory",
"Combinatorics",
"Mathematical relations",
"Mechanics"
] |
66,488,224 | https://en.wikipedia.org/wiki/Pholiota%20vernalis | Pholiota vernalis is a species of fungus belonging to the family Strophariaceae.
It has cosmopolitan distribution.
References
Strophariaceae
Fungus species | Pholiota vernalis | [
"Biology"
] | 34 | [
"Fungi",
"Fungus species"
] |
66,488,238 | https://en.wikipedia.org/wiki/Comodule%20over%20a%20Hopf%20algebroid | In mathematics, at the intersection of algebraic topology and algebraic geometry, there is the notion of a Hopf algebroid which encodes the information of a presheaf of groupoids whose object sheaf and arrow sheaf are represented by algebras. Because any such presheaf will have an associated site, we can consider quasi-coherent sheaves on the site, giving a topos-theoretic notion of modules. Duallypg 2, comodules over a Hopf algebroid are the purely algebraic analogue of this construction, giving a purely algebraic description of quasi-coherent sheaves on a stack: this is one of the first motivations behind the theory.
Definition
Given a commutative Hopf-algebroid a left comodule pg 302 is a left -module together with an -linear mapwhich satisfies the following two properties
(counitary)
(coassociative)
A right comodule is defined similarly, but instead there is a mapsatisfying analogous axioms.
Structure theorems
Flatness of Γ gives an abelian category
One of the main structure theorems for comodulespg 303 is if is a flat -module, then the category of comodules of the Hopf-algebroid is an abelian category.
Relation to stacks
There is a structure theorem pg 7 relating comodules of Hopf-algebroids and modules of presheaves of groupoids. If is a Hopf-algebroid, there is an equivalence between the category of comodules and the category of quasi-coherent sheaves for the associated presheaf of groupoidsto this Hopf-algebroid.
Examples
From BP-homology
Associated to the Brown-Peterson spectrum is the Hopf-algebroid classifying p-typical formal group laws. Notewhere is the localization of by the prime ideal . If we let denote the idealSince is a primitive in , there is an associated Hopf-algebroid There is a structure theorem on the Adams-Novikov spectral sequence relating the Ext-groups of comodules on to Johnson-Wilson homology, giving a more tractable spectral sequence. This happens through an equivalence of categories of comodules of to the category of comodules of giving the isomorphismassuming and satisfy some technical hypotheses pg 24.
See also
Adams spectral sequence
Steenrod algebra
References
Hopf algebras
Homotopical algebra
Algebraic topology
Algebraic geometry | Comodule over a Hopf algebroid | [
"Mathematics"
] | 524 | [
"Fields of abstract algebra",
"Topology",
"Algebraic topology",
"Algebraic geometry"
] |
66,488,949 | https://en.wikipedia.org/wiki/Emma%20Allen-Vercoe | Emma Allen-Vercoe is a British-Canadian Molecular biologist who is a Professor and Canada Research Chair at the University of Guelph. Her research considers the gut microbiome and microbial therapeutics to treat Escherichia coli.
Early life and education
Allen-Vercoe was an undergraduate student at the Veterinary Laboratories Agency. She moved to the Health Protection Agency for her graduate studies, where she worked under the supervision of Martin Woodward. Here she studied Salmonella enterica and the processes by which enteric pathogens cause disease. She was a postdoctoral researcher at the Health Protection Agency. During her doctorate, she studied Mycobacterium tuberculosis and Campylobacter jejuni.
Research and career
In 2001, Allen-Vercoe moved to Canada, where she joined the University of Calgary. Allen-Vercoe worked on Escherichia coli. In 2004, she was awarded a Canadian Association of Gastroenterology Fellow-to-Faculty Transition Award. She moved to the University of Guelph in 2007. Her research considers the gut microbiome. She worked with the biotechnology company Infors to create a bioreactor that can maintain biological samples in specific anaerobic atmospheres whilst her research team studying the constituents microbes.
Allen-Vercoe isolates bacteria from human stool samples, places them in the so-called robo-gut and monitors their behaviour in precise conditions. For example, the robo-gut (or mechanical colon) can recreate environments that allow for particular genes and bacteria to thrive, which allows Allen-Vercoe to study the microbiobes associated with certain medical conditions. Allen-Vercoe has identified the general bacteria that exist in all microbiomes, as well as monitoring the microbiome's metabolomics. She has worked on microbial therapeutics to treat various diseases, including Clostridioides difficile infection and cancer.
Allen-Vercoe launched the NuBiyota in 2013, a biotechnology company that looks to grow microbes in a controlled environment. She was awarded a Tier 1 Canada Research Chair in 2019, which allowed her to study the influence of the gut microbiome on health and disease.
Selected publications
References
Women veterinary scientists
Veterinary scientists
Molecular biologists
Canada Research Chairs
Academic staff of the University of Guelph
Academic staff of the University of Calgary
Living people
Year of birth missing (living people) | Emma Allen-Vercoe | [
"Chemistry"
] | 495 | [
"Biochemists",
"Molecular biology",
"Molecular biologists"
] |
66,488,978 | https://en.wikipedia.org/wiki/Lachnellula%20willkommii | Lachnellula willkommii is a species of fungus belonging to the family Lachnaceae.
It is native to Eurasia and Northern America.
References
Helotiales
Fungus species | Lachnellula willkommii | [
"Biology"
] | 40 | [
"Fungi",
"Fungus species"
] |
66,489,058 | https://en.wikipedia.org/wiki/Drepanopeziza%20sphaerioides | Drepanopeziza sphaerioides is a species of fungus belonging to the family Drepanopezizaceae.
Synonym: Marssonina salicicola (Bres.) Magnus, 1906
References
Helotiales
Fungus species | Drepanopeziza sphaerioides | [
"Biology"
] | 52 | [
"Fungi",
"Fungus species"
] |
66,489,065 | https://en.wikipedia.org/wiki/Geometric%20rigidity | In discrete geometry, geometric rigidity is a theory for determining if a geometric constraint system (GCS) has finitely many -dimensional solutions, or frameworks, in some metric space. A framework of a GCS is rigid in -dimensions, for a given if it is an isolated solution of the GCS, factoring out the set of trivial motions, or isometric group, of the metric space, e.g. translations and rotations in Euclidean space. In other words, a rigid framework of a GCS has no nearby framework of the GCS that is reachable via a non-trivial continuous motion of that preserves the constraints of the GCS. Structural rigidity is another theory of rigidity that concerns generic frameworks, i.e., frameworks whose rigidity properties are representative of all frameworks with the same constraint graph. Results in geometric rigidity apply to all frameworks; in particular, to non-generic frameworks.
Geometric rigidity was first explored by Euler, who conjectured that all polyhedra in -dimensions are rigid. Much work has gone into proving the conjecture, leading to many interesting results discussed below. However, a counterexample was eventually found. There are also some generic rigidity results with no combinatorial components, so they are related to both geometric and structural rigidity.
Definitions
The definitions below, which can be found in, are with respect to bar-joint frameworks in -dimensional Euclidean space, and will be generalized for other frameworks and metric spaces as needed. Consider a linkage , i.e. a constraint graph with distance constraints assigned to its edges, and the configuration space consisting of frameworks of . The frameworks in consist of maps that satisfy
for all edges of . In other words, is a placement of the vertices of as points in -dimensions that satisfy all distance constraints . The configuration space is an algebraic set.
Continuous and trivial motions. A continuous motion is a continuous path in that describes the physical motion between two frameworks of that preserves all constraints. A trivial motion is a continuous motion resulting from the Euclidean isometries, i.e. translations and rotations. In general, any metric space has a set of trivial motions coming from the isometric group of the space.
Local rigidity. A framework of a GCS is locally rigid, or just rigid, if all its continuous motions are trivial.
Testing for local rigidity is co-NP hard.
Rigidity map. The rigidity map takes a framework and outputs the squared-distances between all pairs of points that are connected by an edge.
Rigidity matrix. The Jacobian, or derivative, of the rigidity map yields a system of linear equations of the form
for all edges of . The rigidity matrix is an matrix that encodes the information in these equations. Each edge of corresponds to a row of and each vertex corresponds to columns of . The row corresponding to the edge is defined as follows.
Infinitesimal motion. An infinitesimal motion is an assignment of velocities to the vertices of a framework such that . Hence, the kernel of the rigidity matrix is the space of infinitesimal motions. A trivial infinitesimal motion is defined analogously to a trivial continuous motion.
Stress. A stress is an assignment to the edges of a framework . A stress is proper if its entries are nonnegative and is a self stress if it satisfies . A stress satisfying this equation is also called a resolvable stress, equilibrium stress, prestress, or sometimes just a stress.
Stress Matrix. For a stress applied to the edges of a framework with the constraint graph , define the stress matrix as
.
It is easily verified that for any two and any stress ,
The rigidity matrix as a linear transformation
The information in this section can be found in. The rigidity matrix can be viewed as a linear transformation from to . The domain of this transformation is the set of column vectors, called velocity or displacements vectors, denoted by , and the image is the set of edge distortion vectors, denoted by . The entries of the vector are velocities assigned to the vertices of a framework , and the equation describes how the edges are compressed or stretched as a result of these velocities.
The dual linear transformation leads to a different physical interpretation. The codomain of the linear transformation is the set of column vectors, or stresses, denoted by , that apply a stress to each edge of a framework . The stress applies forces to the vertices of that are equal in magnitude but opposite in direction, depending on whether is being compressed or stretched by . Consider the equation where is a vector. The terms on the left corresponding to the columns of a vertex in yield the entry in that is the net force applied to by the stresses on edges incident to . Hence, the domain of the dual linear transformation is the set of stresses on edges and the image is the set of net forces on vertices. A net force can be viewed as being able to counteract, or resolve, the force , so the image of the dual linear transformation is really the set of resolvable forces.
The relationship between these dual linear transformations is described by the work done by a velocity vector under a net force :
where is a stress and is an edge distortion. In terms of the stress matrix, this equation above becomes .
Types of rigidity
This section covers the various types of rigidity and how they are related. For more information, see.
Infinitesimal rigidity
Infinitesimal rigidity is the strongest form of rigidity that restricts a framework from admitting even non-trivial infinitesimal motions. It is also called first-order rigidity because of its relation to the rigidity matrix. More precisely, consider the linear equations
resulting from the equation . These equations state that the projections of the velocities and onto the edge cancel out. Each of the following statements is sufficient for a -dimensional framework to be infinitesimally rigid in -dimensions:
all its infinitesimal motions are trivial;
the dimension of the kernel of is ; or
the rank of is .
In general, any type of framework is infinitesimally rigid in -dimensions if space of its infinitesimal motions is the space of trivial infinitesimal motions of the metric space. The following theorem by Asimow and Roth relates infinitesimal rigidity and rigidity.
Theorem. If a framework is infinitesimally rigid, then it is rigid.
The converse of this theorem is not true in general; however, it is true for generic rigid frameworks (with respect to infinitesimal rigidity), see combinatorial characterizations of generically rigid graphs.
Static rigidity
A -dimensional framework is statically rigid in -dimensions if every force vector on the vertices of that is orthogonal to the trivial motions can be resolved by the net force of some proper stress ; or written mathematically, for every such force vector there exists a proper stress such that
Equivalently, the rank of must be . Static rigidity is equivalent to infinitesimal rigidity.
Second-order rigidity
Second-order rigidity is weaker than infinitesimal and static rigidity. The second derivative of the rigidity map consists of equations of the form
The vector assigns an acceleration to each vertex of a framework . These equations can be written in terms of matrices: ,
where is defined similarly to the rigidity matrix. Each of the following statements are sufficient for a -dimensional framework to be second-order rigid in -dimensions:
every solution pair to the equation above consists of a trivial infinitesimal motion ;
for every non-trivial infinitesimal motion , there is no acceleration satisfying the equation above; or
for each non-trivial infinitesimal motion , there is some equilibrium stress such that .
The third statement shows that for each such , is not in the column span of , i.e., it is not an edge distortion resulting from . This follows from the Fredholm alternative: since the column span of is orthogonal to the kernel of , i.e., the set of equilibrium stresses, either for some acceleration or there is an equilibrium stress satisfying the third condition. The third condition can be written in terms of the stress matrix: . Solving for is a non-linear problem in with no known efficient algorithm.
Prestress stability
Prestress stability is weaker than infinitesimal and static rigidity but stronger than second-order rigidity. Consider the third sufficient condition for second-order rigidity. A -dimensional framework is prestress stable if there exists an equilibrium stress such that for all non-trivial velocities , . Prestress stability can be verified via semidefinite programming techniques.
Global rigidity
A -dimensional framework of a linkage is globally rigid in -dimensions if all frameworks in the configuration space are equivalent up to trivial motions, i.e., factoring out the trivial motions, there is only one framework of .
Theorem. Global rigidity is a generic property of graphs.
Minimal rigidity
A -dimensional framework is minimally rigid in -dimensions if is rigid and removing any edge from results in a framework that is not rigid.
Redundant rigidity
There are two types of redundant rigidity: vertex-redundant and edge-redundant rigidity. A -dimensional framework is edge-redundantly rigid in -dimensions if is rigid and removing any edge from results in another rigid framework. Vertex-redundant rigidity is defined analogously.
Rigidity for various types of frameworks
Polyhedra
This section concerns the rigidity of polyhedra in -dimensions, see polyhedral systems for a definition of this type of GCS. A polyhedron is rigid if its underlying bar-joint framework is rigid. One of the earliest results for rigidity was a conjecture by Euler in 1766.
Conjecture. A closed spatial figure allows no changes, as long as it is not ripped apart.
Much work has gone into proving this conjecture, which has now been proved false by counterexample. The first major result is by Cauchy in 1813 and is known as Cauchy's theorem.
Cauchy's Theorem. If there is an isometry between the surfaces of two strictly convex polyhedra which is an isometry on each of the faces, then the two polyhedra are congruent.
There were minor errors with Cauchy's proof. The first complete proof was given in, and a slightly generalized result was given in. The following corollary of Cauchy's theorem relates this result to rigidity.
Corollary. The 2-skeleton of a strictly convex polyhedral framework in -dimensions is rigid.
In other words, if we treat the convex polyhedra as a set of rigid plates, i.e., as a variant of a body-bar-hinge framework, then the framework is rigid. The next result, by Bricard in 1897, shows that the strict convexity condition can be dropped for -skeletons of the octahedron.
Theorem. The -skeleton of any polyhedral framework of the octahedron in -dimensions is rigid. However, there exists a framework of the octahedron whose -skeleton is not rigid in -dimensions.
The proof of the latter part of this theorem shows that these flexible frameworks exist due to self-intersections. Progress on Eurler's conjecture did not pick up again until the late 19th century. The next theorem and corollary concern triangulated polyhedra.
Theorem. If vertices are inserted in the edges of a strictly convex polyhedron and the faces are triangulated, then the -skeleton of the resulting polyhedron is infinitesimally rigid.
Corollary. If a convex polyhedron in -dimensions has the property that the collection of faces containing a given vertex do not all lie in the same plane, then the -skeleton of that polyhedron is infinitesimally rigid.
The following result shows that the triangulation condition in the above theorem is necessary.
Theorem. The -skeleton of a strictly convex polyhedron embedded in -dimensions which has at least one non-triangluar face is not rigid.
The following conjecture extends Cauchy's result to more general polyhedra.
Conjecture. Two combinatorially equivalent polyhedra with equal corresponding dihedral angles are isogonal.
This conjecture has been proved for some special cases. The next result applies in the generic setting, i.e., to almost all polyhedra with the same combinatorial structure, see structural rigidity.
Theorem. Every closed simply connected polyhedral surface with a -dimensional framework is generically rigid.
This theorem demonstrates that Euler's conjecture is true for almost all polyhedra. However, a non-generic polyhedron was found that is not rigid in -dimensions, disproving the conjecture. This polyhedra is topologically a sphere, which shows that the generic result above is optimal. Details on how to construct this polyhedra can be found in. An interesting property of this polyhedra is that its volume remains constant along any continuous motion path, leading to the following conjecture.
Bellows Conjecture. Every orientable closed polyhedral surface flexes with constant volume.
This conjecture was first proven for spherical polyhedra and then in general.
Tensegrities
This section concerns the rigidity of tensegrities, see tensegrity systems for a definition of this type of GCS.
Definitions
The definitions below can be found in.
Infinitesimal motion. An infinitesimal motion of a tensegrity framework is a velocity vector such that for each edge of the framework,
, if is a bar;
, if is a cable; and
, if is a strut.
Second-order motion. A second-order motion of a tensegrity framework is a solution to the following constraints:
Bar constraint: and ;
Cable constraint: and or ; and
Cable constraint: and or .
Global rigidity.’ A -dimensional tensegrity framework of a tensegrity GCS is globally rigid in -dimensions if every other -dimensional framework of the same GCS that is dominated by can be obtained via a trivial motion of .
Universal rigidity. A -dimensional tensegrity framework of a tensegrity GCS is universally rigid if it is globally rigid in any dimension.
Dimensional rigidity. A -dimensional tensegrity framework of a tensegrity GCS is dimensionally rigid in -dimensions if any other -dimensional tensegrity framework , for any satisfying the constraints of the GCS, has an affine span of dimension at most .
Super stable. A -dimensional tensegrity framework is super stable in -dimensions if is rigid in -dimensions as a bar-joint framework and has a proper equilibrium stress such that the stress matrix is positive semidefinite and has rank .
Rigidity theorems
Generic results.
Infinitesimal rigidity is not a generic property of tensegrities, see structural rigidity. In other words, not all generic tensegrities with the same constraint graph have the same infinitesimal rigidity properties. Hence, some work has gone into identifying specific classes of graphs for which infinitesimal rigidity is a generic property of tensegrities. Graphs satisfying this condition are called strongly rigid. Testing a graph for strong rigidity is NP-hard, even for -dimension. The following result equates generic redundant rigidity of graphs to infinitesimally rigid tensegrities.
Theorem. A graph has an infinitesimally rigid tensegrity framework in -dimensions, for some partition of the edges of into bars, cables, and struts if and only if is generically edge-redundantly rigid in -dimensions.
The first result demonstrates when rigidity and infinitesimal rigidity of tensegrities are equivalent.
Theorem. Let be a -dimensional tensegrity framework where: the vertices of are realized as a strictly convex polygon; the bars form a Hamilton cycle on the boundary of this polygon; and there are no struts. Then, is rigid in -dimensions if and only if it is infinitesimally rigid in -dimensions.
The following is a necessary condition for rigidity.
Theorem. Let be a -dimensional tensegrity framework with at least one cable or strut. If is rigid in -dimensions, then it has a non-zero proper equilibrium stress.
Rigidity of tensegrities can also be written in terms of bar-joint frameworks as follows.
Theorem. Let be a -dimensional tensegrity framework with at least one cable or strut. Then is infinitesimally rigid in -dimensions if it is rigid in -dimensions as a bar-joint framework and has a strict proper stress.
The following is a sufficient condition for second-order rigidity.
Theorem. Let be a -dimensional tensegrity framework. If for all non-trivial infinitesimal motions of , there exists a proper equilibrium stress such that
then is second-order rigid.
An interesting application of tensegrities is in sphere-packings in polyhedral containers. Such a packing can be modelled as a tensegrity with struts between pairs of tangent spheres and between the boundaries of the container and the spheres tangent to them. This model has been studied to compute local maximal densities of these packings.
The next result demonstrates when tensegrity frameworks have the same equilibrium stresses.
Theorem. Let be a -dimensional tensegrity framework with a proper stress such that the stress matrix is positive semidefinite. Then, is a proper stress of all -dimensional tensegrity frameworks dominated by .
Global rigidity theorems
The following is a sufficient condition for global rigidity of generic tensegrity frameworks based on stress matrices.
Theorem. Let be a -dimensional generic tensegrity framework with a proper equilibrium stress . If the stress matrix has rank , then is globally rigid in dimensions.
While this theorem is for the generic setting, it does not offer a combinatorial characterization of generic global rigidity, so it is not quite a result of structural rigidity.
Universal and dimensional rigidity
Let be a -dimensional generic tensegrity framework, such that the affine span of is , with a proper equilibrium stress and the stress matrix . A finite set of non-zero vectors in lie on a conic at infinity if, treating them as points in -dimensional projective space, they lie on a conic. Consider the following three statements:
is positive semidefinite.
.
The edge directions of with a non-zero stress, and bars, do not lie on a conic at infinity.
If Statements 1 and 2 hold, then is dimensionally rigid in -dimensions, and if Statement 3 also holds, then is universally rigid in -dimensions.
References
Geometry | Geometric rigidity | [
"Mathematics"
] | 3,831 | [
"Geometry"
] |
66,489,313 | https://en.wikipedia.org/wiki/Lactarius%20azonites | Lactarius azonites is a species of fungus belonging to the family Russulaceae.
It is native to Europe and Northern America.
References
azonites
Fungus species | Lactarius azonites | [
"Biology"
] | 36 | [
"Fungi",
"Fungus species"
] |
66,490,111 | https://en.wikipedia.org/wiki/Geiringer%E2%80%93Laman%20theorem | The Geiringer–Laman theorem gives a combinatorial characterization of generically rigid graphs in -dimensional Euclidean space, with respect to bar-joint frameworks. This theorem was first proved by Hilda Pollaczek-Geiringer in 1927, and later by Gerard Laman in 1970. An efficient algorithm called the pebble game is used to identify this class of graphs. This theorem has been the inspiration for many Geiringer-Laman type results for other types of frameworks with generalized pebble games.
Statement of the theorem
This theorem relies on definitions of genericity that can be found on the structural rigidity page. Let denote the vertex set of a set of edges .
Geiringer-Laman Theorem. A graph is generically rigid in -dimensions with respect to bar-joint frameworks if and only if has a spanning subgraph such that
for all subsets , .
The spanning subgraph satisfying the conditions of the theorem is called a Geiringer-Laman, or minimally rigid, graph. Graphs satisfying the second condition form the independent sets of a sparsity matroid, and are called -sparse. A graph satisfying both conditions is also called a -tight graph. The direction of the theorem which states that a generically rigid graph is -tight is called the Maxwell direction, because James Clerk Maxwell gave an analogous necessary condition of -sparsity for a graph to be independent in the -dimensional generic rigidity matroid. The other direction of the theorem is the more difficult direction to prove. For dimensions , a graph that is -tight is not necessarily generically minimally rigid, i.e., the converse of the Maxwell Direction is not true.
Example. Consider the graphs in Figure 1. The graph in (c) is generically minimally rigid, but it is not infinitesimally rigid. The red velocity vectors depict a non-trivial infinitesimal flex. Removing the red edge in (a) yields a generically minimally rigid spanning graph. Adding the dashed red edge in (b) makes the graph generically minimally rigid.
Theorem. Let be a graph. The following statements are equivalent:
is a generically minimally rigid;
is -tight; and
contains three edge-disjoint spanning trees and such that (i) each vertex of is contained in exactly two of these spanning trees and (ii) distinct subtrees of these spanning trees do not have the same vertex set.
The equivalence of the first and second statements is the Geiringer-Laman theorem. The equivalence of the first and third statements was first proved by Crapo via the Geiringer-Laman theorem, and later by Tay via a more direct approach.
Outline of proof
The proof of the Geiringer-Laman theorem given below is based on Laman's proof. Furthermore, the details of the proofs below are based on lecture notes found here
Consider a bar-joint system and a framework of this system, where is a map that places the vertices of in the plane such that the distance constraints are satisfied. For convenience, we refer to as a framework of . The proof of the Geiringer-Laman theorem follows the outline below.
A graph is generically rigid if and only if it is generically infinitesimally rigid.
Infinitesimal rigidity is a generic property of graphs.
Rigidity is a generic property of graphs.
If a framework is infinitesimally rigid, then it is rigid.
If a framework is generic with respect to infinitesimally rigidity and rigid, then it is infinitesimally rigid.
If a graph has a generic infinitesimally rigid framework, then is a Geiringer-Laman graph.
A graph is a Geiringer-Laman graph if and only if has a Henneberg construction.
If a graph has a Henneberg construction, then has a generic infinitesimally rigid framework.
Step 1 sets up the generic setting of rigidity so that we can focus on generic infinitesimal rigidity rather than generic rigidity. This is an easier approach, because infinitesimal rigidity involves a system of linear equations, rather than quadratic in the case of regular rigidity. In particular, we can prove structural properties about the rigidity matrix of a generic framework. These results were first proved by Asimow and Roth, see Combinatorial characterizations of generically rigid graphs. Note that in Step 1.4 the framework must be generic with respect to infinitesimal rigidity. In particular, a framework that is rigid and generic with respect to rigidity is not necessarily infinitesimally rigid. Step 2 is the Maxwell Direction of the proof, which follows from simple counting arguments on the rigidity matrix. Step 3 shows that generically minimally rigid graphs are exactly the graphs that can be constructed starting from a single edge using two simple operations, which are defined below. Step 4 shows that graphs with this type of construction are generically infinitesimally rigid. Finally, once Step 1 is proved, Steps 2-3 prove the Geiringer-Laman theorem.
Equivalence of generic rigidity and generic infinitesimal rigidity
Let be a graph. First, we show that generic frameworks with respect to infinitesimal rigidity form an open and dense set in . One necessary and sufficient condition for a framework of to be infinitesimally rigid is for its rigidity matrix to have max rank over all frameworks of .
Proposition 1. For any framework of and any neighborhood , there exists a framework in such that the rigidity matrix has max rank.
Proof. If the rigidity matrix does not have max rank, then it has a set of dependent rows corresponding to a subset of edges such that for some other rigidity matrix , the rows corresponding to are independent. Let be the set of frameworks such that the rows corresponding to in their rigidity matrices are dependent. In other words, is the set of frameworks such that the minor of the rows corresponding to in is . Hence, is a curve in , because a minor is a polynomial in the entries of a matrix. Let be the union of these curves over all subsets of edges of . If a framework does not have max rank for some framework , then is contained in . Finally, since is a finite set of curves, the proposition is proved.
Proposition 2. Infinitesimal rigidity is a generic property of graphs.
Proof. We show that if one generic framework with respect to infinitesimal rigidity is infinitesimally rigid, then all generic frameworks are infinitesimally rigid. If a framework of a graph is infinitesimally rigid, then has max rank. Note that the kernel of the rigidity matrix is the space of infinitesimal motions of a framework, which has dimension for infinitesimally rigid frameworks. Hence, by the Rank–nullity theorem, if one generic framework is infinitesimally rigid then all generic frameworks are infinitesimal rigidity have rigid.
Proposition 3. If a framework of a graph is infinitesimally rigid, then it is rigid.
Proof. Assume that is not rigid, so there exists a framework in a neighborhood such that and is cannot be obtained via a trivial motion of . Since is in , there exists a and such that . Applying some algebra yields:
Hence,
We can choose a sequence of such that and . This causes and . Hence,
The first and last expressions in the equations above state that is an infinitesimal motion of the framework . Since there is no trivial motion between and , is not a trivial infinitesimal motion. Thus, is not infinitesimally rigid.
Proposition 4. If a framework of a graph is rigid and generic with respect to infinitesimal rigidity, then is infinitesimally rigid.
Proof. This follows from the implicit function theorem. First, we will factor out all trivial motions of . Since has max rank, no points of are colinear. Hence, we can pin points of to factor out trivial motions: one point at the origin and another along the -axis at a distance from the origin consistent with all constraints. This yields a pinned framework that lives in . This can be done for all frameworks in a neighborhood of to obtain a neighborhood of of pinned frameworks. The set of such frameworks is still a smooth manifold, so the rigidity map and rigidity matrix can be redefined on the new domain. Specifically, the rigidity matrix of a pinned framework has columns and rank equal to , where is the unpinned framework corresponding to . In this pinned setting, a framework is rigid if it is the only nearby solution to the rigidity map.
Now, assume an unpinned framework is not infinitesimally rigid, so that . Then the , where is the pinned version of . We now set up to apply the implicit function theorem. Our continuously differentiable function is the rigidity map . The Jacobian of is the rigidity matrix. Consider the subset of edges corresponding to the independent rows of , yielding the submatrix . We can find independent columns of . Denote the entries in these columns by the vectors . Denote the entries of the remaining columns by the vectors . The submatrix of induced the is invertible, so by the implicit function theorem, there exists a continuously differentiable function such that and . Hence, the framework of the subgraph is not rigid, and since the rows of span the row space of , is also not rigid. This contradicts our assumption, so is infinitesimally rigid.
Proposition 5. Rigidity is a generic property of graphs.
Proof. Let be a rigid framework of that is generic with respect to rigidity. By definition, there is a neighborhood of rigid frameworks of . By Proposition 1, there is a framework in that is generic with respect to infinitesimal rigidity, so by Proposition 4, is infinitesimally rigid. Hence, by Proposition 2, all frameworks that are generic with respect to infinitesimal rigidity are infinitesimally rigid, and by Proposition 3 they are also rigid. Finally, every neighborhood of every framework that is generic with respect to rigidity contains a framework that is generic with respect to infinitesimal rigidity, by Proposition 1. Thus, if is rigid then is rigid.
Theorem 1. A graph is generically rigid if and only if it is generically infinitesimally rigid.
Proof. The proof follows a similar argument to the proof of Proposition 5. If is generically rigid, then there exists a generic framework with respect to rigidity that is rigid by definition. By Propositions 1 and 4, in any neighborhood of there is a framework that is generic with respect to infinitesimal rigidity and infinitesimally rigid. Hence, by Proposition 2, is generically infinitesimally rigid.
For the other direction, assume to the contrary that is generically infinitesimally rigid, but not generically rigid. Then there exists a generic framework with respect to rigidity that is not rigid by definition. By Proposition 1, in any neighborhood of there is a framework that is generic with respect to infinitesimal rigidity. By assumption is infinitesimally rigid, and by Proposition 3, is also rigid. Thus, must be rigid and, by Proposition 5, all frameworks that are generic with respect to rigidity are rigid. This contradicts our assumption that is not generically rigid.
Maxwell direction
The Maxwell Direction of the Geiringer-Laman theorem follows from a simple counting argument on the rigidity matrix.
Maxwell Direction. If a graph has a generic infinitesimally rigid framework, then has a Geiringer-Laman subgraph.
Proof. Let be a generic infinitesimally rigid framework of . By definition, has max rank, i.e., . In particular, has independent rows. Each row of corresponds to an edge of , so the submatrix with just the independent rows corresponds to a subgraph such that . Furthermore, any subgraph of corresponds to a submatrix of . Since the rows of are independent, so are the rows of . Hence, , which clearly satisfies .
Equivalence of generic infinitesimal rigidity and Henneberg constructions
Now we begin the proof of the other direction of the Geiringer-Laman theorem by first showing that a generically minimally rigid graph has a Henneberg construction. A Henneberg graph has the following recursive definition:
is a single edge or
can be obtained from a Henneberg graph via one of the following operations
add a vertex to and connect it to distinct vertices of
For an edge and a vertex of , add a vertex to , connect it to and , and then remove .
The two operations above are called a -extension and a -extension respectively.
The following propositions are proved in:
Proposition 6. A generically minimally rigid graph has no vertex with degree and at least one vertex with degree less than
Proposition 7. If is a generically minimally rigid graph with a vertex of degree , connected to vertices and , then for at least one pair of the neighbors of , without loss of generality say , there is no subgraph of that contains and and satisfies .
Theorem 2. A generically minimally rigid graph with at least vertices has a Henneberg construction.
Proof. We proceed by induction on the number of vertices . The base case of is the base case Henneberg graph. Assume has a Henneberg construction when and we will prove it for . When , has a vertex with degree or , by Proposition 6.
Case 1: has degree 2.
Let be the subgraph of obtained by removing , so and . Since is minimally rigid, we have
Furthermore, any subgraph of is also a subgraph of , so by assumption. Hence, is minimally rigid, by the Maxwell Direction, and has a Henneberg construction by the inductive hypothesis. Now simply notice that can be obtained from via a -extension.
Case 2: has degree 3.
Let the edges incident to be and . By Proposition 7, for one pair of the neighbors of , without loss of generality say , there is no subgraph of that contains and and satisfies . Note that cannot be an edge, or else the subgraph on just that edge satisfies the previous equality. Consider the graph obtained by removing from and adding the edge . We have
.
Furthermore, as with Case 1, any subgraph of that does not contain satisfies the second condition for minimal rigidity by assumption. For a subgraph of that does contain , removing this edge yields a subgraph of . By Proposition 7, , so . Hence, is minimally rigid, and has a Henneberg construction by the inductive hypothesis. Finally, notice that can be obtained from via a -extension.
Combining Cases 1 and 2 proves the theorem by induction.
It is also easy to the converse of Theorem 2 by induction.
Proposition 8. A graph with a Henneberg construction is generically minimally rigid.
Henneberg constructible graphs are generically infinitesimally rigid
To complete the proof of the Geringer-Laman theorem, we show that if a graph has a Henneberg construction then it is generically infinitesimmaly rigid. The proof of this result relies on the following proposition from.
Proposition 9. If are three non-colinear -dimensional points and are three -dimensional vectors, then the following statements are equivalent:
for all
The function
vanishes at every point .
Theorem 3. If a graph with at least vertices has a Henneberg construction, then is generically infinitesimally rigid.
Proof. We proceed by induction on the number of vertices . The graph in the base case is a triangle, which is generically infinitesimally rigid. Assume that when is generically infinitesimally rigid and we will prove it for . For , consider the graph that was obtained from via - or -extension. By the inductive hypothesis, is generically infinitesimally rigid. Hence, has a generic infinitesimally rigid framework such that the kernel of has dimension . Let be the vertex added to to obtain . We must choose a placement in -dimensions such that is a generic infinitesimally rigid framework of .
Case 1: is obtained from via a -extension.
Choosing such a placement for is equivalent to adding rows corresponding to the equations
to the rigidity matrix , where and are the neighbors of after the -extension and is the velocity assigned to by an infinitesimal motion. Our goal is to choose such the dimension of the space of infinitesimal motions of is the same as that of . We can choose such that it is not colinear to and , which ensures that there is only one solution to these equations. Hence, the kernel of has dimension , so is a generic infinitesimally rigid framework of .
Case 2: is obtained from via a -extension.
Let the neighbors of after the -extension be the edges , and , and let be the edge that was removed. Removing the edge from yields the subgraph . Let be the framework of that is equivalent to , except for the removed edge. The rigidity matrix can be obtained from by removing the row corresponding to the removed edge. By Proposition 8, is generically minimally rigid, so the rows of are independent. Hence, the rows of are independent and its kernel has dimension . Let be a basis vector for the space of infinitesimal motions of such that is a basis for the space of trivial infinitesimal motions. Then, any infinitesimal motion of can be written as a linear combination of these basis vectors. Choosing a placement for that results in a generic infinitesimally rigid framework of is equivalent to adding rows corresponding to the equations
to the rigidity matrix . Our goal is to choose such the dimension of the space of infinitesimal motions of is less than that of . After rearranging, these equations have a solution if and only if
Note that can be written as , for constants . Furthermore, we can move the summation outside of the determinant to obtain
Since form a basis for the trivial infinitesimal motions, the first three terms in the summation are , leaving only
Solutions to this equation form a curve in -dimensions. We can choose not along this curve so that , which ensures that there is only one solution to this equation. Hence, by Proposition 9, the kernel of has dimension , so is a generic infinitesimally rigid framework of .
Combining Cases 1 and 2 proves the theorem by induction.
See also
Laman graph
References
Theorems in graph theory | Geiringer–Laman theorem | [
"Physics",
"Mathematics"
] | 3,816 | [
"Theorems in graph theory",
"Mathematics of rigidity",
"Mechanics",
"Theorems in discrete mathematics"
] |
66,490,345 | https://en.wikipedia.org/wiki/WASP-88 | WASP-88 is a F-type main-sequence star. Its surface temperature is 6450 K. WASP-88 is similar to the Sun in its concentration of heavy elements, with a metallicity Fe/H index of 0.03, and is younger at an age of 3.0 billion years.
A multiplicity survey did detect a candidate red dwarf companion to WASP-88 in 2020, with a 1.65% probability of it being an unrelated background star.
Planetary system
In 2013, one planet, named WASP-88b, was discovered on a tight, circular orbit. The planet is highly inflated, and may be an easy target for atmospheric characterization. Planetary equilibrium temperature is 1775 K. The planetary atmosphere transmission spectrum is gray and featureless, probably indicating a large concentration of hazes.
References
Indus (constellation)
Planetary transit variables
F-type main-sequence stars
Planetary systems with one confirmed planet
J20380268-4827434 | WASP-88 | [
"Astronomy"
] | 195 | [
"Indus (constellation)",
"Constellations"
] |
66,491,048 | https://en.wikipedia.org/wiki/Arvid%20Reuterdahl | Arvid Reuterdahl (February 15, 1876 – January 13, 1933) was a Swedish-American engineer, scientist and educator.
Biography
Reuterdahl was born at Karlstad on February 15, 1876. He moved to the United States as a child in 1882. He graduated Sc.B. from Brown University in 1897 and was a mathematics and physics instructor at the Technical High School in Providence. Reuterdahl worked as an engineer in Spokane, Washington for five years and as an assistant city engineer, water commissioner and President of the board of public works. He designed bridges for the city. He was an consulting engineer of Boise, Idaho (1910–1913) and Kansas City, Missouri (1913–1918).
He was professor of theoretical and applied mechanics at Kansas City Polytechnic Institute (1915–1918) and was the first Dean of the Department of Engineering and Architecture at the College of St. Thomas (1918–1922). He was President of the Ramsey Institute of Technology, Saint Paul, Minnesota (1922-1926).
He was a Fellow of the American Association for the Advancement of Science. He married Elinor Morrison on June 16, 1902. They had one son, Norman Morrison Reuterdahl.
Opposition to the theory of relativity
Reuterdahl was a noted opponent of Albert Einstein's theory of relativity. He considered Einstein's theory to be largely "bunk" and accused him of plagiarism. Reuterdahl argued that Einstein's theory of relativity was plagiarized from a mechanical gravitation theory of Scottish engineer Robert Stevenson (pseudonym Kinertia). He argued that Stevenson's papers were sent to the Prussian Academy of Sciences in 1903 and that Einstein, a member of the Academy secretly made use of the papers.
Reuterdahl communicated with other anti-relativists such as Ernst Gehrcke. He was science editor for Henry Ford's journal the Dearborn Independent.
Selected publications
Scientific Theism Versus Materialism: The Space-time Potential (1920)
Einstein and the New Science (1921)
"Kinertia" Versus Einstein (1921)
A Synthesis of Number, Space-Time and Energy (1923)
The God of Science (1928)
Einsteinism: Its Fallacies and Frauds (1931)
References
1876 births
1933 deaths
20th-century American engineers
Brown University alumni
Fellows of the American Association for the Advancement of Science
People from Karlstad
Relativity critics
Swedish emigrants to the United States
University of St. Thomas (Minnesota) faculty | Arvid Reuterdahl | [
"Physics"
] | 509 | [
"Relativity critics",
"Theory of relativity"
] |
66,491,075 | https://en.wikipedia.org/wiki/WASP-84 | WASP-84, also known as BD+02 2056, is a G-type main-sequence star away in the constellation Hydra. Its surface temperature is 5350 K and is slightly enriched in heavy elements compared to the Sun, with a metallicity Fe/H index of 0.05. It is rich in carbon and depleted of oxygen. WASP-84's age is probably older than the Sun at 8.5 billion years. The star appears to have an anomalously small radius, which can be explained by the unusually high helium fraction or by it being very young.
A multiplicity survey did not detect any stellar companions to WASP-84 as of 2015.
Planetary system
In 2013, one exoplanet, named WASP-84b, was discovered on a tight, circular orbit. The planet is a hot Jupiter that cannot have formed in its current location and likely migrated from elsewhere. The planetary orbit is well aligned with the equatorial plane of the star, misalignment being equal to 0.3°. Planetary equilibrium temperature is 832 K.
In 2023, a second planet was discovered around WASP-84. This appears to be a dense rocky planet despite its high mass, comparable to Uranus.
References
Hydra (constellation)
Planetary transit variables
G-type main-sequence stars
Planetary systems with two confirmed planets
J08442570+0151361
BD+02 2056 | WASP-84 | [
"Astronomy"
] | 290 | [
"Hydra (constellation)",
"Constellations"
] |
66,491,838 | https://en.wikipedia.org/wiki/Kenneth%20Z.%20Altshuler | Kenneth Z. Altshuler (April 11, 1929 – January 6, 2021) was an American psychiatrist and psychoanalyst. He was a Professor Emeritus of Psychiatry and the Chairman of the Department of Psychiatry at the University of Texas Southwestern Medical Center in Dallas.
Early life and education
Kenneth Z. Altshuler was born on April 11, 1929, in Paterson, New Jersey, to Jacob and Altie Altshuler. He graduated from Cornell University in 1948 and received his M.D. degree from the University at Buffalo, School of Medicine in 1952, at age 23. He did an internship at Kings County Hospital Center. From 1953–1955, he served in the Navy leaving the service with the rank of Lt. (J.G.) in the Medical Corps. After the military service, he underwent a specialty training in psychiatry and psychoanalysis at Columbia University Center for Psychoanalytic Training and Research.
Career
In 1973, Altshuler joined the Columbia University faculty where he focused on the research of mental illnesses among deaf patients and in geriatric psychiatry. From 1973–1977, he managed undergraduate education in psychiatry at Columbia University's College of Physicians and Surgeons in New York. In 1977, he left Columbia University and moved to Texas. He became the chairman of the Department of Psychiatry at UT Southwestern Medical Center in Dallas. There, he expanded the faculty from five to over one hundred full-time physicians and raising fifty-two million dollars in departmental endowments, including funds for ten chairs and two research centers. He retired in 2019, and was appointed a Professor Emeritus of Psychiatry.
He served as a director of the National Board of Medical Examiners, as a president of the American Association of Chairs of Departments of Psychiatry in 1990–1991, as a board member and later, in 1996, a president of the American Board of Psychiatry and Neurology. In 1999, he was appointed to the board of the Texas Department of Mental Health and Mental Retardation, by then-Governor George W. Bush, and served for five years. He also served on the boards and advisory boards of the local psychiatric and charity organizations.
Personal life
He had three children from his first marriage, Steven L. Altshuler, Lori L. Altshuler and Dara Altshuler, and six grandchildren. In 1987, he married Ruth Collins Sharp, an American philanthropist. He and his wife were known for their civic engagement in Dallas and philanthropic activities in North Texas, including to UT Southwestern. After his wife died in 2017, he established a fund at UT Southwestern, the Ruth & Ken Altshuler Fund for Clinical Psychiatry and the Kenneth Z. Altshuler Fund for Psychiatric Education, to support clinical research and education programs related to mental illness.
Altshuler died from complications of COVID-19 on January 6, 2021, during the COVID-19 pandemic in Texas.
Awards and honors
Merit Award of the National Psychological Association for Psychoanalysis
Honorary Doctorate of Science from the Gallaudet College for the Deaf
Certificate of Special Achievement by the American Psychiatric Association for contribution to the program for the deaf in New York
Certificate of Special Recognition by the American Psychiatric Association for contribution to the Community Mental Health program in Dallas
Distinguished Alumnus Award of the University of Buffalo School of Medicine
Trail Blazer Award by the Dallas Community Mental Health Center
Wilson Award in Geriatric Psychiatry
Psychiatric Excellence Award from the Texas Society of Psychiatric Physicians
Texas Star Award from the Texas Mental Health Association
Outstanding Psychiatric Award from the North Texas Society of Psychiatric Physicians
Prism Award from the Dallas Mental Health Association
The Psychiatric Out-Patient Clinic of Dallas Community Mental Health Center is named in his honor
The Psychiatric Unit of Zale Lipshy Pavilion is named in his honor
The Callier Center for Communication Disorders at University of Texas at Dallas established an annual award bearing his name – the Ruth and Ken Altshuler Callier Care Award
The Metrocare Services established a research center bearing his name – the Altshuler Center for Education and Research
Dallas County Mental Health and Mental Retardation renamed one of its clinics in his honor – the Kenneth Z. Altshuler Mental Health Clinic
See also
Ruth Sharp Altshuler
Lori L. Altshuler
References
1929 births
2021 deaths
Physicians from Dallas
Physicians from Paterson, New Jersey
Military personnel from New Jersey
American psychiatrists
Cornell University alumni
University at Buffalo alumni
Columbia University Vagelos College of Physicians and Surgeons alumni
University of Texas Southwestern Medical Center faculty
Sleep researchers
Deaths from the COVID-19 pandemic in Texas | Kenneth Z. Altshuler | [
"Biology"
] | 901 | [
"Sleep researchers",
"Behavior",
"Sleep"
] |
76,812,905 | https://en.wikipedia.org/wiki/TikTok%20Shop | TikTok Shop is an e-commerce feature of the video hosting service TikTok. Officially launched in September 2023, the feature enables users interested in starting a business and generating income to upload their curated products on TikTok for others to discover and purchase. Daily sales averaged approximately US$7 million in October 2023.
History
In October 2020, TikTok announced its partnership with Shopify for a feature called TikTok: For Business. This collaboration laid the groundwork for the eventual launch of TikTok Shop.
In November 2022, ByteDance commenced beta testing of the platform in the United Kingdom and several Southeast Asian countries. In December 2022, Amazon announced the release of Amazon Inspire, a platform resembling TikTok Shop, in a bid to compete with TikTok itself.
In September 2023, ByteDance announced the launch of TikTok Shop globally, which was notably influenced by Amazon Inspire.
Criticism and controversies
Since its launch, TikTok Shop has encountered issues related to misinformation about products, reviews made by generative artificial intelligence to promote certain products, review bombs, and instances of scamming.
References
TikTok
E-commerce
2022 establishments
ByteDance | TikTok Shop | [
"Technology"
] | 248 | [
"Information technology",
"E-commerce"
] |
76,816,166 | https://en.wikipedia.org/wiki/Edmone%20Roffael | Edmone Roffael (1939–2021) was a Palestinian-German chemist and wood scientist, and former professor at the Georg-August University of Göttingen, who made noteworthy contributions to clarifying the release of formaldehyde from particleboard and MDF products, and its emission reduction.
Roffael was a honorary fellow of the International Academy of Wood Science.
From 1993 to 2005, Roffael served as the head of the Department of Wood Chemistry and Wood Technology at the Institute of Wood Biology and Wood Technology, Faculty of Forest Sciences and Forest Ecology at the Georg-August University of Göttingen. His yearlong research work has held a worldwide recognition.
Biography
Edmone Roffael was born on December 31, 1939, in Tulkarm, Palestine. Initially, he studied chemistry in Egypt at University of Alexandria and Cairo University, as well as at the Technical University of Darmstadt in Germany.
After completing his studies, he obtained a Ph.D. in cellulose chemistry from TU Darmstadt in 1968, with a dissertation titled "X-ray and infrared investigations on the orderliness of cellulose." Subsequently, he worked from 1970 to 1993 at the Fraunhofer Institute for Wood Research in Braunschweig, where he was engaged in technological wood research, cooperating also with the-then director, Dr. Rainer Marutzky. His work focus soon became various particleboard materials and their production using synthetic resins, mostly formaldehyde-based resins (UF, MUF, PF). Regarding this topic, Roffael authored his habilitation thesis, titled "Possibilities of gluing wood particles with phenol-formaldehyde resins and sulfite liquor," which resulted in his habilitation at the Faculty of Forestry at the Georg-August University of Göttingen in 1976 and granted him the teaching qualification (venia legendi) for the subject of "Wood Chemistry."
Beginning in 1981, Roffael taught as an adjunct professor at the Faculty of Forestry at the University of Göttingen. In 1993, he accepted the appointment to the Chair of Wood Science at Goettingen University. In the following years, he established the Wood Chemistry Department at the Institute of Forest Utilization, and in 1997, the entire institution was renamed to as "Institute of Wood Biology and Wood Technology".
Roffael gained international recognition primarily through his contributions to formaldehyde research. He had focused his scientific attention on this issue publishing the seminal work "Die Formaldehyd-Abgabe von Spanplatten und anderen Werkstoffen" in 1982. However, it was only in the years following that the topic garnered widespread public attention, especially due to serious concerns about the potential health risks and the hazards for the public health. That work was updated and translated into Russian (1991) and English (1993). The methods and devices for measuring the then-found carcinogenic formaldehyde emissions from materials, which Roffael co-developed, were the basis for the development of the German (DIN) and European (EN) standards, guidelines, and regulations. Roffael continuously sought ways to minimize the off-gassing of these substances. He also conducted research on other so-called volatile organic compounds (VOCs) emitted from raw wood and glued wood products. Roffael was also heavily involved in the development of tannin-bonded particleboard panels.
He held numerous patents. In addition, more than 20 doctoral theses and more than 40 D.Sc. and M.Sc. theses were performed under his scientific guidance. Roffael was very active in numerous committees and associations, served for the former German Society for Wood Research (DGfH e.V.) in several expert committees. In addition, he was regular member of the Euro Wood Network, the United Nations Environment Programme Working Group, the Zellcheming Association and the Cellulose-Chemists-Club Darmstadt. He also participated as a member in the editorial boards of the estemmed wood-related journals, Holzforschung and European Journal of Wood and Wood Products.
Even after his retirement in 2005, he continued to be active in scientific research at Goettingen University, coordinating various research projects. In 2017, he published the book "Formaldehyde in Nature, Wood and Wood Materials", both in German and English.
Edmone Roffael died in Braunschweig in January 2021.
Recognition
During his career, Roffael published his research findings primarily in journals such as WKI-Mitteilungen, Holz als Roh- und Werkstoff, Holz-Zentralblatt, and Das Papier. By 2019, he had authored over 900 scientific and technical publications of any kind.
His research work enjoyed a worldwide recognition. His various research and consulting activities took him to Egypt, Brazil, Bulgaria, Chile, Canada, Malaysia, Sweden, Syria, Turkey, and the USA. He has had fruitful research collaboration also in Greece, with the chemical resin company, Chimar Hellas.
In 1988, Roffael, along with his fellows Marutzky and Mehlhorn, were awarded by the International Association iVTH for their research work on the topic "Investigations on the formaldehyde emissions from wood-based materials and other materials, and the development of methods to reduce formaldehyde emission potential."
On the occasion of his 65th birthday, the Faculty of Forest Sciences and Forest Ecology at the University of Göttingen honored him on April 21, 2005, with a symposium on "Wood Industry and Wood Products in Transition." Approximately 120 participants from academia and industry gathered in the auditorium at Wilhelmsplatz to celebrate.
In October 2023, a meta-research carried out by John Ioannidis et al. at Stanford University, included Edmone Roffael in Elsevier Data 2022, where he was ranked at the top 2% of researchers in wood science (forestry – materials), having a composite index of 3.0892.
Selected works
"Röntgen- und Infrarotuntersuchungen über den Ordnungszustand der Cellulose" (X-ray and Infrared Studies on the Orderliness of Cellulose), dissertation, Darmstadt 1968
"Möglichkeiten der Verleimung von Holzspänen mit Phenolformaldehydharzen und Sulfitablauge" (Possibilities of Gluing Wood Particles with Phenol-Formaldehyde Resins and Sulfite Liquor), habilitation thesis, Göttingen 1975/1976
"Beiträge zur Verwendung von alkalischen Phenolformaldehyharzen [Phenolformaldehydharzen] und Ligninsulfonaten bei der Verleimung von Holzspänen" (Contributions to the Use of Alkaline Phenol-Formaldehyde Resins and Lignosulfonates in Gluing Wood Particles), WKI-Bericht No. 8, Braunschweig 1976
"Die Formaldehyd-Abgabe von Spanplatten und anderen Werkstoffen" (Formaldehyde Emissions from Particleboard and Other Materials), Stuttgart 1982 (ISBN 3-87181-301-X; Russian translation 1991, English translation 1993)
Edited with Rainer Grießhammer: "Verwendung von Durchforstungsholz und Altpapier zur Papierherstellung unter Berücksichtigung forstwirtschaftlicher Belange" (Use of Thinned Wood and Waste Paper in Papermaking, Considering Forestry Aspects), Luft, Boden, Abfall (Issue 37), Stuttgart 1995
"Umweltschutz in der Holzwerkstoffindustrie. Fachtagung am 24. und 25. Juni 1998 in Göttingen. Tagungsband" (Environmental Protection in the Wood-Based Materials Industry. Conference Proceedings, June 24-25, 1998, Göttingen), Göttingen 1999
Together with Claus Behn: "Untersuchungen zur Verminderung der Längenänderung von Holzspanplatten durch gezielte Nutzung von materialimmanenten Eigenschaften und Verwendung von feuchtebeständigen Zusatzstoffen. Schlussbericht. Laufzeit: 01.07.1999 bis 31.08.2003" (Investigations into Reducing the Length Changes of Particleboard by Utilizing Intrinsic Properties and Using Moisture-Resistant Additives. Final Report. Project Duration: 01.07.1999 to 31.08.2003), Göttingen 2004
Bibliography
"Professor Dr.-Ing. Edmone Roffael" (2021). European Journal of Wood and Wood Products, 79 (3): 509-510; doi=10.1007/s00107-021-01693-3
N.N.: "Prof. Dr.-Ing. Edmone Roffael, 65 Jahre" (Prof. Dr.-Ing. Edmone Roffael, 65 Years). In: "Holz-Zentralblatt", 131st Year, Issue 9/2005, p. 124,
J. Fischer: "„Sie haben zu unser aller Lebensqualität beigetragen“. Festkolloquium anlässlich des 65. Geburtstages von Prof. Edmonde [sic!] Roffael – große Verdienste bei der Formaldehyd-Forschung" (""You Have Contributed to All Our Quality of Life." Symposium on the Occasion of Prof. Edmone Roffael's 65th Birthday – Great Achievements in Formaldehyde Research"). In: "Holz-Zentralblatt", 131st Year, Issue 35/2005, pp. 435 and 438,
References
External links
Google Scholar
E. Roffael (1939-2021)
1939 births
2021 deaths
20th-century Palestinian people
20th-century German scientists
Fellows of the International Academy of Wood Science
German people of Palestinian descent
Palestinian scientists
People from Tulkarm
Wood scientists | Edmone Roffael | [
"Materials_science"
] | 2,109 | [
"Wood sciences",
"Wood scientists"
] |
76,816,751 | https://en.wikipedia.org/wiki/LMC%20X-1 | LMC X-1 is the first X-ray source detected in the Large Magellanic Cloud. It was discovered in 1969, using data from an instrument carried by a Sandia Terrier-Sandhawk sounding rocket, launched from the Johnston Atoll on October 29, 1968. LMC X-1 is a persistently luminous X-ray binary.
In the 80s Hutchings et al. performed spectroscopic follow-up observations of the optical counterpart and found an orbital period of about 4 days and a secondary mass of about 6 , making the secondary a stellar mass black hole. The orbital period later turned out to be shorter at around 3.9 days. The optical counterpart is also called "star 32". The black hole has a mass of around 11 and the star has a mass of around 32 and a radius of 17 . With this radius the star nearly fills its Roche lobe and it is predicted that it will encounter its Roche lobe in a few hundred thousand years. Once it reaches its Roche lobe, it will begin rapid and possibly unstable mass transfer to its companion.
The X-ray source is surrounded by a nebula, which is the only nebula energized by an X-ray binary. It is suspected that the nebula is a bow shock nebula. The nebula is also detected in radio wavelengths with ATCA imaging. A possible origin of LMC X-1 is the star cluster [NKN2005] N159-O1. Other possible origins are NGC 2077, NGC 2080, NGC 2085 and NGC 2086. In the scenario of N159-O1 being the origin, the progenitor to the black hole would have a mass of about 60 , meaning it was the most massive member of this star cluster.
See also
M33 X-7 is a stellar mass black hole in the Triangulum Galaxy
Cyg X-1 another x-ray binary with a stellar black hole and a massive star
Gaia BH1 first dormant black hole
References
Stellar black holes
O-type stars
X-ray binaries
Dorado
Astronomical objects discovered in 1969 | LMC X-1 | [
"Physics",
"Astronomy"
] | 426 | [
"Black holes",
"Stellar black holes",
"Dorado",
"Unsolved problems in physics",
"Constellations"
] |
76,817,298 | https://en.wikipedia.org/wiki/De%20novo%20domestication | De novo domestication is a process where new species are genetically altered to meet human needs, such as agriculture or companionship. It is performed both by farmers and scientists, and can be done through traditional selective breeding or modern biotechnological methods. Targets for de novo domestication are often species that have never been under cultivation, but may also include wild relatives of already domesticated species.
Definition
De novo domestication refers to the process by which wild species are intentionally transformed into domesticated varieties. The majority of domesticated species has been under domestication for millenia, with the first animal, the dog, having been under domestication for between 40,000-30,000 years, and the first plants since the start of the Neolithic Revolution, approximately 12,000 years ago. This initial process of domestication is hypothesized to have been a passive process, resulting from the subconcious selection of individuals performing better in agricultural contexts. The scientific field of de novo domestication seeks to domesticate new species in an accelerated manner as opposed to over the course of thousands of years, as more domesticated species may provide an advantage to humanity, especially in agriculture. Newly domesticated crop species may allow for alternatives to agricultural extensification in regions where yields are plateauing, make agricultural systems more resilient to climate change, and increase the sustainability of agriculture.
It is important to note that de novo domestication does not only happen in a scientific context, but that the active domestication of new species is also performed by farmers, especially in the Global South. The collection and subsequent agricultural integration of traditionally wild-gathered food plants still happens to this day, and also constitutes de novo domestication.
The terminology in the scientific field of domestication is improperly standardized, with the same term meaning different things to different scientists. This means that in some cases, de novo domestication is solely used for species that have no history of domestication, while in other cases, it can be used to describe further studies into semi-domesticated crops, which already have gone through (early) stages of domestication.
In plants
The study of de novo domestication is most prevalent in plants, due to the implications new crops may bring to agriculture. There are two potential applications to the study of de novo domestication in plant sciences: the introduction of novel crops into agricultural systems and the redomestication of wild relatives of conventionally domesticated crops.
Novel species
The introduction of novel species into agricultural systems has the potential to radically alter their workings. One set of candidates for de novo domestication are perennial grains, cereal crops that can be harvested for multiple seasons after planting, as opposed to the annual grains that dominate agriculture. The successful de novo domestication of a perennial grain would drastically reduce the need for yearly plowing, seedling protection and energy spent on reaching maturity, thus decreasing environmental impact and labour use. The de novo domestication of tropical fruit trees is suggested to be able to help address 14 out of 17 of the Sustainable Development Goals set by the United Nations, either directly or indirectly.
Redomestication
Another use for de novo domestication is the redomestication of wild relatives of domesticated crops. Through millennia under selection, most domesticated crops have undergone many genetic bottlenecks, drastically reducing their genetic diversity, and thus the ability to breed in new traits. Meanwhile, these bottlenecked crops have been spread over the entire world, and are often grown in areas with climates that differ significantly from their genetic center of origin. Redomestication of crop wild relatives may offer a solution to long-term, repetitive plant breeding projects seeking to integrate wild relative DNA from the center of origin into established hybrid cultivars. This is especially relevant for crops that are reproductively incompatible with their wild relatives through processes such as polyploidization, such as hexaploid wheat, where integration of wild relative DNA through traditional breeding projects is difficult.
In animals
The de novo domestication of animals has less scientific traction than that of plants, but one notable project is that undertaken by the Russian Institute of Cytology and Genetics to domesticate the fox. This project aimed to study the theory of evolution and domestication syndrome by attempting the domestication of foxes, but was not primarily aimed at providing a new domesticated animal. De novo domestication of fish, either in the ornamental aquarium trade or for the purposes of pisciculture is also ongoing.
In fungi
Fungiculture, the cultivation of fungi such as mushrooms, has historically been less important than horticulture or animal husbandry in providing food for humans. Mushrooms were often gathered from the wild, but the knowledge to do so has largely disappeared in the Global North due to lifestyle changes and urbanization, prompting an increased need for mushroom cultivation. As a result, many fungi were de novo domesticated, such as snow fungus (1866), oyster mushroom (1917), and milky white mushroom (1974). A fungus that has been notoriously difficult to bring under cultivation is white truffle, and projects to de novo domesticate it are running.
See also
Genetic manipulation
References
Genetics
Domestication
Selection
Breeding
Biotechnology | De novo domestication | [
"Biology"
] | 1,042 | [
"Evolutionary processes",
"Behavior",
"Selection",
"Domestication",
"Genetics",
"Reproduction",
"Biotechnology",
"Breeding",
"nan",
"Humans and other species"
] |
76,817,344 | https://en.wikipedia.org/wiki/YZ%20Leonis%20Minoris | YZ Leonis Minoris, also known as SDSS J0926+3624, is a star system in the constellation Leo Minor. It is an AM Canum Venaticorum-type variable star, a type of binary systems with ultra-short periods (between 5 and 70 minutes). It is also an eclipsing binary. The apparent magnitude of the system is generally 19.3m, varying by about two magnitudes due to periodic eclipses and outbursts. The distance to YZ LMi is of .
Characteristics
YZ Leonis Minoris is made up of a white dwarf star and a low-mass donor companion. The white dwarf accretes matter from the companion via a helium-rich accretion disk. The disk around the white dwarf has a size ranging from 18,000 to 90,800 km, which is about 45% of the orbital separation of the components. The temperature of the disk varies from 5,000 K (in the outer parts of the disk) to 23,000 K (in the inner parts of the disk).
YZ Leonis Minoris is a very compact system. The orbital period of the stars is just 28 minutes, making it the eclipsing binary system with the shortest orbital period. The components are separated at a distance of , and the surface-to-surface distance is 167,000 km. It is both an AM Canum Venaticorum variable and an eclipsing variable (eclipsing binary). The white dwarf is partially eclipsed by its donor companion.
The system has a normal apparent magnitude of 19.33m, which is way lower than the limit for naked -eye vision (6.5m), making it not visible to the naked eye. A recent estimate from Gaia DR3 gives a distance of for YZ Leonis Minoris, which is significantly larger than previous estimates (of 460–470 pc).
White dwarf
The primary component of the system is a white dwarf. It has a mass between 0.79 and and a radius of (). The white dwarf's surface gravity is about 200,000 times stronger than Earth's gravity. Its effective temperature is estimated to be at least 17,000K, and Sengupta et al. (2011) found three temperatures between 18,000 and 25,000 K. Its luminosity is about 0.009–0.035 times the solar luminosity. The white dwarf is accreting mass from the companion at a rate of solar masses per year, based on evolutionary models.
Low-mass companion
The secondary component of the system is a low-mass companion. It has a mass estimated to be between 0.027 and (28.3 and ) and its radius is estimated at . The mass of the companion makes it semi-degenerate, it would be fully degenerate if its had a mass close to . Its temperature is estimated to be at , with an upper limit of . The luminosity of the companion is equivalent to 0.00035 times the solar luminosity.
Variability
SDSS J0926+2634 is an AM Canum Venaticorum-type variable star, which is a type of cataclysmic variable system that are ultracompact and deficient in hydrogen, with orbital periods of just some minutes. It is also an eclipsing binary, a type of binary stars where the components eclipse each other, causing variation in the apparent brightness. The American Association of Variable Star Observers also mentions YZ Leonis Minoris as a SU Ursae Majoris-type star (dwarf nova). YZ Leonis Minoris was the first system discovered that is both an eclipsing binary and an AM Canum Venaticorum star. As of 2022, more than 8 such systems are known.
The system presents eclipses every 28 minutes, which decrease the system's apparent magnitude by 2 magnitudes and last about two minutes, in addition to presenting outbursts that make the system's apparent magnitude increase by two magnitudes. YZ Leonis Minoris' mean apparent magnitude is 19.33m, decreasing to 17.11–16.81m during the outbursts. These outbursts happen every 100–200 days and are likely generated by bursts of enhanced mass transfer from donor star to the white dwarf.
YZ Leonis Minoris is the variable-star designation of the system.
Discovery
YZ Leonis Minoris was discovered in 2005 by Anderson et al. in a search for spectroscopically unusual objects, after an examination of spectra of 280,000 SDSS objects. It was discovered together with three other objects: SDSS J0129+3842, SDSS J1411+4812, and SDSS J1552+3201.
See also
Cataclysmic variable star
Leo Minor
AM Canum Venaticorum
AM Canum Venaticorum star
Variable star
Notes
References
AM CVn stars
Eclipsing binaries
White dwarfs
Leo Minor
Leonis Minoris, YZ
Astronomical objects discovered in 2005 | YZ Leonis Minoris | [
"Astronomy"
] | 1,046 | [
"Leo Minor",
"Constellations"
] |
76,817,562 | https://en.wikipedia.org/wiki/Levonadifloxacin | Levonadifloxacin (trade name Emrok) is an antibiotic drug of the fluoroquinolone class. Chemically, it is the (S)-enantiomer of the racemic drug nadifloxacin.
It is approved in India for the treatment of skin and soft tissue infections of Gram-positive bacteria. It is also being studied for potential use against resistant strains of bacteria including Streptococcus pneumoniae, Streptococcus pyogenes, Haemophilus influenzae, and Moraxella catarrhalis.
Levonadifloxacin has poor oral bioavailability. A prodrug of levonadifloxacin with high oral bioavailability, alalevonadifloxacin, has been developed to mitigate this problem.
References
Fluoroquinolone antibiotics
Enantiopure drugs
Piperidines
Carboxylic acids
Heterocyclic compounds with 3 rings | Levonadifloxacin | [
"Chemistry"
] | 206 | [
"Carboxylic acids",
"Stereochemistry",
"Functional groups",
"Enantiopure drugs"
] |
76,817,857 | https://en.wikipedia.org/wiki/Alalevonadifloxacin | Alalevonadifloxacin (trade name Emrok O) is an antibiotic of the fluoroquinolone class. It is a prodrug of levonadifloxacin with increased oral bioavailability. In India, it is approved for the treatment of infections with Gram-positive bacteria.
References
Fluoroquinolone antibiotics
Prodrugs
Carboxylic acids
Piperidines
Heterocyclic compounds with 3 rings
Esters | Alalevonadifloxacin | [
"Chemistry"
] | 99 | [
"Esters",
"Carboxylic acids",
"Functional groups",
"Prodrugs",
"Organic compounds",
"Chemicals in medicine"
] |
76,821,292 | https://en.wikipedia.org/wiki/HD%2085709 | HD 85709 (HR 3915; 14 G. Sextantis; NSV 18292) is a solitary star located in the equatorial constellation Sextans. It is faintly visible to the naked eye as a red-hued point of light with an apparent magnitude of 5.95. The object is located relatively far at a distance of 1,100 light-years based on Gaia DR3 parallax measurements but it is slowly drifting closer with a heliocentric radial velocity of . At its current distance, HD 85709's brightness is diminished with an interstellar extinction of two-tenths of a magnitude and it has an absolute magnitude of −1.30.
HD 85709 has a stellar classification of M2.5 III, indicating that it is an evolved M-type giant star. It is currently on the asymptotic giant branch, the point where it is generating energy via the fusion of hydrogen and helium shells around an inert carbon core. Having expanded to 133 times the radius of the Sun, it now radiates 1,918 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of . HD 85709 is metal enriched with an iron abundance 1.58 times that of the Sun's.
In 1991, astronomer V.G. Kornilov and colleagues observed that HD 85709 fluctuated between magnitudes 5.89 and 5.95 in optical light during a photometry survey. As of 2004 however, its variability has not been confirmed.
References
M-type giants
Suspected variables
Asymptotic-giant-branch stars
Sextans
Sextantis, 14
BD+06 02224
085709
048519
3915 | HD 85709 | [
"Astronomy"
] | 357 | [
"Sextans",
"Constellations"
] |
76,821,357 | https://en.wikipedia.org/wiki/Lifting%20beam | The lifting beam (also known as traverse, spreader beam) is a steel beam that is attached to the hook of the crane in order to spread the slings from one end of an elongated load (like a wall panel) to another. The bottom of the beam has multiple connection points for hanging the load.
The lifting beams are used in multiple cases:
lifting an asymmetrical load. Without a beam, it might be hard to strap the load so that its center of gravity is exactly below the hook;
handling a long load with a single-hook crane. Sufficient spread between the slings prevents the load from slipping out;
increase the headroom: slings cannot be stretched close to the horizontal direction, so attaching them directly to the hook requires a minimum distance from the hook to the load. When the lifting beam is used, the slings can be shorter, providing more vertical clearance during lifting;
if the attachments of the load are on its vertical sides, the slings have to go over the edges of the load, which can damage these edges. A lifting beam allows attaching slings to the side lugs without touching the edges;
the top of the beam can have two attachment points at the ends thus allowing two cranes to share the load.
See also
Container spreader
References
Sources
Lifting equipment | Lifting beam | [
"Physics",
"Technology"
] | 267 | [
"Physical systems",
"Machines",
"Lifting equipment"
] |
76,822,899 | https://en.wikipedia.org/wiki/NGC%203509 | NGC 3509 known as Arp 335, is a barred spiral galaxy located in the constellation Leo. It is located 340 million light-years from the Solar System. NGC 3509 was discovered by astronomer William Herschel on December 30, 1786.
Characteristics
NGC 3509 is a large galaxy. With a diameter of 215,000 light-years, it is much bigger than the Milky Way, which only has a diameter of at least 100,000 light-years. Its luminosity class is II-III and it has a broad HII region.
Additionally, NGC 3509 is a peculiar galaxy showing an interesting detail. It has a sweeping tidal tail feature, which seems to offer hints of evolution and makes the galaxy resemble a tadpole. According to a sketch drew by Toomre, a large tail of NGC 3509 is seen curved towards northwest while the shorter one extends southwest. Later investigations proved him wrong as it is actually a bright ridge of the galaxy's disk structure.
NGC 3509 has a single undisturbed nucleus which is surrounded by dust lanes. This means it has not undergone a major disk-to-disk merger and instead had a minor merger with a smaller satellite galaxy. As the galaxy interaction between NGC 3509 and the galaxy occurs, certain starbursts are triggered in regions along its spiral arms which causes it to actively create new stars. It is also evident, NGC 3509 contain signs of neutral hydrogen.
Another study proves that a galactic halo is growing in NGC 3509 through accretion of smaller galaxies, in which they leave a spur behind as they are tidally disrupted by their host galaxy.
NGC 3509 is designated as Arp 335 in the Atlas of Peculiar Galaxies by Halton Arp, in which it is placed into the Miscellaneous category, M82 being the well-known galaxy in this classification.
Supernova
One supernova has been discovered in NGC 3509: SN 2010bi.
SN 2010bi
SN 2010bi was discovered on March 24, 2010, by G. Piginata and M. Cifuentes along with other astronomers from University of North Carolina at Chapel Hill on the behalf of the CHASE project (CHilean Automatic Supernova sEarch). SN 2010bi was found via an unfiltered image taken using the 0.41-m 'PROMPT 5' telescope located at Cerro Tololo. It was located 28".4 east and 34".6 north of the nucleus. The supernova was Type IIP in which its progenitor might be a 8-16 solar mass red supergiant.
References
Barred spiral galaxies
Interacting galaxies
Leo (constellation)
Discoveries by William Herschel
Astronomical objects discovered in 1786
3509
06134
335
+01-28-033
033446
SDSS objects
2MASS objects
11018+0505
033446 | NGC 3509 | [
"Astronomy"
] | 576 | [
"Leo (constellation)",
"Constellations"
] |
76,823,014 | https://en.wikipedia.org/wiki/Taxonomic%20synonyms%20of%20Solanum%20tuberosum | The potato, Solanum tuberosum, has at least 438 taxonomic synonyms, as listed by the Royal Botanic Gardens, Kew website Plants of the World Online.
Synonyms
The attribution after each synonym is to the authors who first described the species under that name.
Battata tuberosa
Larnax sylvarum subsp. novogranatensis
Lycopersicon tuberosum
Parmentiera edulis
Solanum andigenum
Solanum andigenum convar. acutifolium
Solanum andigenum convar. adpressipilosum
Solanum andigenum f. alccai-huarmi
Solanum andigenum f. ancacc-maquin
Solanum andigenum f. arcuatum
Solanum andigenum subsp. argentinicum
Solanum andigenum subsp. australiperuvianum
Solanum andigenum subsp. aya-papa
Solanum andigenum var. aymaranum
Solanum andigenum f. basiscopum
Solanum andigenum f. bifidum
Solanum andigenum var. bolivianum
Solanum andigenum subsp. bolivianum
Solanum andigenum convar. brachistylum
Solanum andigenum convar. brevicalyces
Solanum andigenum var. brevicalyx
Solanum andigenum convar. brevipilosum
Solanum andigenum f. caesium
Solanum andigenum f. caiceda
Solanum andigenum var. carhua
Solanum andigenum f. ccompetillo
Solanum andigenum f. ccompis
Solanum andigenum var. ccusi
Solanum andigenum subsp. centraliperuvianum
Solanum andigenum f. cevallosii
Solanum andigenum f. chalcoense
Solanum andigenum f. chimaco
Solanum andigenum var. ckello-huaccoto
Solanum andigenum f. coeruleum
Solanum andigenum var. colombianum
Solanum andigenum subsp. colombianum
Solanum andigenum f. conicicolumnatum
Solanum andigenum f. cryptostylum
Solanum andigenum convar. curtibaccatum
Solanum andigenum var. cuzcoense
Solanum andigenum var. digitotuberosum
Solanum andigenum f. dilatatum
Solanum andigenum f. discolor
Solanum andigenum subsp. ecuatorianum
Solanum andigenum convar. elongatibaccatum
Solanum andigenum f. elongatipedicellatum
Solanum andigenum f. globosum
Solanum andigenum var. grauense
Solanum andigenum f. guatemalense
Solanum andigenum var. hederiforme
Solanum andigenum var. herrerae
Solanum andigenum f. huaca-layra
Solanum andigenum var. huairuru
Solanum andigenum f. huallata
Solanum andigenum f. huaman-uma
Solanum andigenum var. imilla
Solanum andigenum f. incrassatum
Solanum andigenum var. juninum
Solanum andigenum f. lanciacuminatum
Solanum andigenum f. lapazense
Solanum andigenum var. latius
Solanum andigenum f. lecke-umo
Solanum andigenum f. lilacinoflorum
Solanum andigenum f. lisarassa
Solanum andigenum f. llutuc-runtum
Solanum andigenum convar. longiacuminatum
Solanum andigenum var. longibaccatum
Solanum andigenum convar. macron
Solanum andigenum f. magnicorollatum
Solanum andigenum var. mexicanum
Solanum andigenum f. microstigma
Solanum andigenum convar. microstigmatum
Solanum andigenum f. nodosum
Solanum andigenum convar. nudiculum
Solanum andigenum convar. obtusiacuminatum
Solanum andigenum f. ovatibaccatum
Solanum andigenum f. pacus
Solanum andigenum f. pallidum
Solanum andigenum var. platyantherum
Solanum andigenum f. pomacanchicum
Solanum andigenum f. ppacc-nacha
Solanum andigenum f. ppaqui
Solanum andigenum convar. puca-mata
Solanum andigenum var. quechuanum
Solanum andigenum var. sihuanum
Solanum andigenum var. socco-huaccoto
Solanum andigenum convar. stenon
Solanum andigenum var. stenophyllum
Solanum andigenum f. sunchchu
Solanum andigenum subsp. tarmense
Solanum andigenum f. tenue
Solanum andigenum f. tiahuanacense
Solanum andigenum convar. titicacense
Solanum andigenum f. tocanum
Solanum andigenum f. tolucanum
Solanum andigenum f. uncuna
Solanum apurimacense
Solanum aracatscha
Solanum aracc-papa
Solanum ascasabii
Solanum boyacense
Solanum caniarense
Solanum cardenasii
Solanum cayeuxi
Solanum chariense
Solanum chaucha
Solanum chaucha var. ccoe-sulla
Solanum chaucha var. ckati
Solanum chaucha var. khoyllu
Solanum chaucha var. puca-suitu
Solanum chaucha f. purpureum
Solanum chaucha f. roseum
Solanum chaucha var. surimana
Solanum chiloense
Solanum chilotanum
Solanum chilotanum var. angustifurcatum
Solanum chilotanum f. magnicorollatum
Solanum chilotanum f. parvicorollatum
Solanum chilotanum var. talukdarii
Solanum chocclo
Solanum churuspi
Solanum coeruleiflorum
Solanum cultum
Solanum diemii
Solanum dubium
Solanum erlansonii
Solanum esculentum
Solanum estradea
Solanum goniocalyx
Solanum goniocalyx var. caeruleum
Solanum herrerae
Solanum hygrothermicum
Solanum kesselbrenneri
Solanum leptostigma
Solanum leptostigma
Solanum macmillanii
Solanum maglia var. chubutense
Solanum maglia var. guaytecarum
Solanum mamilliferum
Solanum molinae
Solanum oceanicum
Solanum ochoanum
Solanum paramoense
Solanum parmentieri
Solanum parvicorollatum
Solanum phureja
Solanum phureja var. caeruleum
Solanum phureja var. erlansonii
Solanum phureja subsp. estradae
Solanum phureja var. flavum
Solanum phureja subsp. hygrothermicum
Solanum phureja var. janck'o-phureja
Solanum phureja var. macmillanii
Solanum phureja f. orbiculatum
Solanum phureja var. pujeri
Solanum phureja var. rubroroseum
Solanum phureja var. sanguineum
Solanum phureja f. sayhuanimayo
Solanum phureja f. timusi
Solanum phureja f. viuda
Solanum riobambense
Solanum rybinii
Solanum rybinii var. bogotense
Solanum rybinii var. boyacense
Solanum rybinii var. pastoense
Solanum rybinii var. popayanum
Solanum sabinei
Solanum sanmartinense
Solanum sendigena
Solanum sinense
Solanum stenotomum
Solanum stenotomum f. alcay-imilla
Solanum stenotomum f. canasense
Solanum stenotomum f. canastilla
Solanum stenotomum f. catari-papa
Solanum stenotomum f. ccami
Solanum stenotomum var. ccami
Solanum stenotomum var. chapina
Solanum stenotomum f. chilcas
Solanum stenotomum f. chincherae
Solanum stenotomum f. chojllu
Solanum stenotomum f. cochicallo
Solanum stenotomum f. cohuasa
Solanum stenotomum f. cuchipacon
Solanum stenotomum var. cyaneum
Solanum stenotomum f. eucaliptae
Solanum stenotomum subsp. goniocalyx
Solanum stenotomum f. huallata-chinchi
Solanum stenotomum f. huamanpa-uman
Solanum stenotomum f. huanuchi
Solanum stenotomum var. huicu
Solanum stenotomum f. kamara
Solanum stenotomum f. kantillero
Solanum stenotomum var. keccrana
Solanum stenotomum f. kehuillo
Solanum stenotomum f. koso-nahui
Solanum stenotomum var. megalocalyx
Solanum stenotomum f. negrum
Solanum stenotomum f. orcco-amajaya
Solanum stenotomum f. pallidum
Solanum stenotomum var. peruanum
Solanum stenotomum f. phinu
Solanum stenotomum f. phitu-huayacas
Solanum stenotomum f. piticana
Solanum stenotomum var. pitiquilla
Solanum stenotomum f. pitoca
Solanum stenotomum var. poccoya
Solanum stenotomum f. puca
Solanum stenotomum var. puca-lunca
Solanum stenotomum var. putis
Solanum stenotomum f. roseum
Solanum stenotomum f. tiele
Solanum stenotomum f. yana-cculi
Solanum stenotomum f. yuracc
Solanum subandigenum
Solanum sylvestre
Solanum tarmense
Solanum tascalense
Solanum tenuifilamentum
Solanum tuberosum f. acuminatum
Solanum tuberosum var. aethiopicum
Solanum tuberosum var. alaudinum
Solanum tuberosum var. album
Solanum tuberosum f. alkka-imilla
Solanum tuberosum f. alkka-silla
Solanum tuberosum f. amajaya
Solanum tuberosum subsp. andigenum
Solanum tuberosum var. anglicum
Solanum tuberosum f. araucanum
Solanum tuberosum f. auriculatum
Solanum tuberosum f. azul-runa
Solanum tuberosum var. batatinum
Solanum tuberosum var. bertuchii
Solanum tuberosum var. borsdorfianum
Solanum tuberosum var. brachyceras
Solanum tuberosum f. brachykalukon
Solanum tuberosum f. brevipapillosum
Solanum tuberosum var. brevipilosum
Solanum tuberosum var. bufoninum
Solanum tuberosum var. californicum
Solanum tuberosum f. camota
Solanum tuberosum var. cepinum
Solanum tuberosum f. chaped
Solanum tuberosum f. chiar-lelekkoya
Solanum tuberosum f. chiar-pala
Solanum tuberosum subsp. chiloense
Solanum tuberosum var. chiloense
Solanum tuberosum var. chilotanum
Solanum tuberosum f. chojo-sajama
Solanum tuberosum var. chubutense
Solanum tuberosum f. conicum
Solanum tuberosum var. conocarpum
Solanum tuberosum f. contortum
Solanum tuberosum f. coraila
Solanum tuberosum var. cordiforme
Solanum tuberosum var. corsicanum
Solanum tuberosum f. crassifilamentum
Solanum tuberosum var. crassipedicellatum
Solanum tuberosum var. cucumerinum
Solanum tuberosum var. cultum
Solanum tuberosum var. drakeanum
Solanum tuberosum var. elegans
Solanum tuberosum f. elongatum
Solanum tuberosum var. elongatum
Solanum tuberosum f. enode
Solanum tuberosum var. erythroceras
Solanum tuberosum var. fragariinum
Solanum tuberosum var. guaytecarum
Solanum tuberosum var. hassicum
Solanum tuberosum var. helenanum
Solanum tuberosum var. hispanicum
Solanum tuberosum var. holsaticum
Solanum tuberosum f. huaca-zapato
Solanum tuberosum f. huichinkka
Solanum tuberosum f. indianum
Solanum tuberosum f. infectum
Solanum tuberosum f. isla-imilla
Solanum tuberosum f. jancck'o-kkoyllu
Solanum tuberosum f. janck'o-chockella
Solanum tuberosum f. janck'o-pala
Solanum tuberosum var. julianum
Solanum tuberosum var. kaunitzii
Solanum tuberosum f. kunurana
Solanum tuberosum f. laram-lelekkoya
Solanum tuberosum f. latum
Solanum tuberosum var. laurentianum
Solanum tuberosum var. lelekkoya
Solanum tuberosum var. leonhardianum
Solanum tuberosum f. mahuinhue
Solanum tuberosum var. malcachu
Solanum tuberosum var. melanoceras
Solanum tuberosum var. menapianum
Solanum tuberosum var. merceri
Solanum tuberosum f. milagro
Solanum tuberosum f. montticum
Solanum tuberosum var. multibaccatum
Solanum tuberosum var. murukewillu
Solanum tuberosum f. nigrum
Solanum tuberosum var. nobile
Solanum tuberosum var. norfolcicum
Solanum tuberosum var. nucinum
Solanum tuberosum f. oculosum
Solanum tuberosum f. ovatum
Solanum tuberosum f. overita
Solanum tuberosum var. palatinatum
Solanum tuberosum var. pecorum
Solanum tuberosum var. peruvianum
Solanum tuberosum f. pichuna
Solanum tuberosum f. pillicuma
Solanum tuberosum var. platyceras
Solanum tuberosum var. polemoniifolium
Solanum tuberosum var. praecox
Solanum tuberosum var. praedicandum
Solanum tuberosum f. pulo
Solanum tuberosum var. putscheanum
Solanum tuberosum var. recurvatum
Solanum tuberosum var. reniforme
Solanum tuberosum var. rockii
Solanum tuberosum var. rossicum
Solanum tuberosum var. rubrisuturatum
Solanum tuberosum var. rugiorum
Solanum tuberosum var. runa
Solanum tuberosum var. sabinei
Solanum tuberosum var. saccharatum
Solanum tuberosum var. salamandrinum
Solanum tuberosum f. sani-imilla
Solanum tuberosum var. schnittspahnii
Solanum tuberosum f. sebastianum
Solanum tuberosum var. sesquimensale
Solanum tuberosum var. sicha
Solanum tuberosum var. sipancachi
Solanum tuberosum var. strobilinum
Solanum tuberosum f. surico
Solanum tuberosum var. taraco
Solanum tuberosum var. tener
Solanum tuberosum f. tenuipedicellatum
Solanum tuberosum f. thalassinum
Solanum tuberosum var. tinctorium
Solanum tuberosum f. tinguipaya
Solanum tuberosum var. ulmense
Solanum tuberosum var. versicolor
Solanum tuberosum var. villaroella
Solanum tuberosum f. viride
Solanum tuberosum var. vuchefeldicum
Solanum tuberosum var. vulgare
Solanum tuberosum var. vulgare
Solanum tuberosum f. wila-huaycku
Solanum tuberosum f. wila-imilla
Solanum tuberosum f. wila-k'oyu
Solanum tuberosum f. wila-monda
Solanum tuberosum f. wila-pala
Solanum tuberosum var. xanthoceras
Solanum tuberosum f. yurac-taraco
Solanum tuberosum var. yutuense
Solanum utile
Solanum yabari
Solanum yabari var. cuzcoense
Solanum yabari var. pepino
Solanum zykinii
References
Solanum
Lists of plants | Taxonomic synonyms of Solanum tuberosum | [
"Biology"
] | 3,682 | [
"Lists of biota",
"Lists of plants",
"Plants"
] |
76,823,092 | https://en.wikipedia.org/wiki/Arp%2060 | Arp 60 also known as LEDA 1762846, is a barred spiral galaxy located in Coma Berenices. It is located 958 million light-years from the Solar System and has an approximate diameter of 95,000 light-years.
Companion galaxy
Arp 60 has one companion galaxy which is located east: SDSS J131446.02+260629.8 known as PGC 4538493. The galaxy is located 979 million light-years away and as such makes a galaxy pair with Arp 60. Together, they are part of the Atlas of Peculiar Galaxies which was created by Halton Arp. In this category, they fall under the classification of Spiral Galaxies with Small, high surface brightness companions.
References
Coma Berenices
1762846
SDSS objects
Barred spiral galaxies
060
2MASS objects | Arp 60 | [
"Astronomy"
] | 172 | [
"Coma Berenices",
"Constellations"
] |
76,824,179 | https://en.wikipedia.org/wiki/Golden%20ochre | Golden ochre, less often Gold Ochre (, от yellow-pale, orange or french ochre (obsolete)) — one of the most famous and brightly colored varieties of ochre — is a natural or (rarely) artificial pigment. In terms of mineral composition, golden ochre is clay with an admixture of aluminosilicates and a high content of the yellow dye itself, iron hydroxide, most often in the form of brown iron ore or limonite. The exact composition of ochre and its impurities vary greatly depending on the place of origin.
Golden ochre is one of the oldest paints, known as a painting material since the times of cave paintings. In wall painting it is one of the main yellow pigments. Golden ochre has good density, the same covering power, high light fastness, pure color and soft structure. To this day it is used in all painting techniques without exception.
Description and properties
The golden ochre pigment is a natural mixture that consists primarily of crystalline iron oxide hydrate with some clay. The closest to golden ochre among related minerals is light ochre, which has a less warm and rich color. If in light ochre the content of the main dye, iron oxide hydrate, is quite low and ranges from 12 to 25%, then in golden ochre its amount can reach 70-75%. As a result, light ochre has a yellow color of a cooler tone and weaker color saturation and is considered a paint that is not bright and not intense. Golden ochre differs from it in its earthy tint and warmer tone.
Yellow ochres are more common in nature than others due to the abundance of their constituent minerals. When heated, orange and yellow ochre release water and gradually darken, acquiring an increasingly reddish tint. This occurs due to the transformation of iron hydroxide into a dark red anhydrous oxide (iron ochre). With controlled calcination of yellow ochre, almost the entire range of shades can be obtained from yellow and orange to red or brown.
Among other varieties of ochres, it was golden ochre that was valued above others; it was classified as the highest category of pigments in this category. In the 18th-19th centuries, golden ochre was supplied to the rest of Europe and Russia from the province of Rousillon, as a result of which the second name of this paint for a long time was French ochre. Of the total number of ochres, it is the golden ochre pigment that is closer in purity, brightness and shade all to Attic ochre, the most highly valued yellow paint of Ancient Greece and Rome.
Until the mid-20th century, picturesque yellow ochres were traditionally divided into fawn, yellow, saffron yellow, golden and orange. In the modern artist's palette, four types of nominal yellow ochre are most often encountered: light, medium, golden and dark. Natural and Italian sienna can also be considered among the same paints. In terms of composition, golden ochre should include at least 53% Fe2O3, 5% Al2O3 and 34% SiO2 with the complete absence of impurities such as CaO, MgO, MnO2 and insoluble sulfates. For comparison: of all yellow ochres, only dark ochre contains more iron oxide (more than 60%).
History and use
Golden ochre is best known as a mineral pigment common in nature, primarily for artistic paints. It has been found since ancient times in rock paintings, frescoes of Ancient Egypt, Greece and Rome. This pigment was also constantly used when painting temples and in icon painting. When analyzing the colorful composition of the icons of Theophan the Greek, despite all the restraint of his color scheme, golden ochre was clearly established.
Golden ochre is also used in the production and restoration of expensive types of furniture. For example, when oil gilding on levkas (gesso), several layers of golden ochre are first applied in oil, and then, after drying and grinding, they are coated with oil gulfarbene varnish. As a result, the surface for gilding is perfectly matte and retains the color of the foil. Gilding on carvings looks especially impressive if shiny polished areas alternate with matte ones.
As an artist's paint, golden ochre has traditionally been a staple in artists palettes, primarily in oil painting, but also in tempera (including watercolor) and more recently, acrylic. It is stable both in pure form and in mixtures. However, when writing with tempera or watercolor, it is necessary to take into account one feature of ochre, dictated by its mineral nature: with a large amount of water-soluble film former, there is a risk of pigment precipitation (both alumina and iron hydroxide), so it is recommended to use ochre in the form of a thick paste.
The muted, slightly "earthy" shade of golden ochre makes it possible to achieve a soft and warm color palette of the painting and, in mixtures with brighter paints, to slightly "reduce" their color activity. There is one more feature. It is generally recommended to avoid very large, raised strokes with pure ochre, since due to the slow and incomplete drying of the layers to the full depth, uneven color and irregular matte surface may appear. The disadvantages of golden ochre include its vulnerability in case of close friction with metal (for example, in the case of rubbing with a palette knife). After some time, such contact can cause the ochre to turn green.
Often light ochre or golden ochre is used to give the painting the impression of external monochrome or unity of color, and also to ensure that the light in the painting does not look colder than the shadow. In this case, ochre performs not only the function of enhancing the feeling of unity of the picture, but also an additional "warming" color.
Golden ochre has been known and widely used as a stable, reliable and inexpensive pigment for any finishing, household and decorative purposes, suitable for painting both interior and exterior work. It does not fade and can withstand almost any weather conditions. A description of a similar use of golden ochre can be found in one of the stories of the Russian writer Sergeev-Tsensky: «...The hives were squat, wide, on four oak logs each, with pitched roofs, covered here with iron, here with plywood, but uniformly painted with golden ochre, cheerful in appearance».
Along with other types of ochre, golden ochre is traditionally widely used in tinting and painting ceramics.
See also
Ochre
Attic ochre
Ochre (disambiguation)
Iron ochre
Clay
List of inorganic pigments
List of colors
Yellow
References
Shades of yellow
Shades of brown
Pigments
Prehistoric art
Paints
Iron oxide pigments
Clay | Golden ochre | [
"Chemistry"
] | 1,419 | [
"Paints",
"Coatings"
] |
76,824,481 | https://en.wikipedia.org/wiki/74%20Geminorum | 74 Geminorum (f Geminorum) is a K-type giant star in the constellation Gemini. It is located about 640 light-years from Earth based on its Gaia DR3 parallax. The star is often subject to lunar occultations, allowing an accurate measurement of its angular diameter. It has an apparent magnitude of 5.05, making it faintly visible to the naked eye.
Characteristics
Based on its spectral type of K5.5III, it is a star that has left the main sequence and evolved into a K-type giant star. It radiates about 670 times the solar luminosity from its photosphere at an effective temperature of 3,933 K. The angular diameter, as measured by a lunar occultation, is . At the current distance of , as measured by a Hipparcos parallax of 6.13 milliarcseconds, it gives a physical size of .
74 Geminorum has an apparent magnitude of 5.05, making it visible to the naked eye only from locations with dark skies, far from light pollution. The absolute magnitude, i.e. the magnitude of the star if it was seen at , is -1.01. It is located in the coordinates RA , DEC , which is within the Gemini constellation. The star is moving away from Earth at a velocity of 25.38 km/s. f Geminorum is the star's Bayer designation. Other designations for the star include 74 Geminorum (the Flamsteed designation), HIP 37300 (from the Hipparcos catalogue), HR 2938 (from the Bright Star Catalogue) and HD 61338 (from the Henry Draper Catalogue).
The star is often subject to lunar occultations. One of these occultations were observed by the SAO RAS 6-m telescope, which allowed the angular diameter of 74 Geminorum to be accurately measured at .
See also
List of stars in Gemini
Notes
References
Gemini (constellation)
K-type giants
Geminorum, 74
Geminorum, f
Durchmusterung objects
061338
037300
2938 | 74 Geminorum | [
"Astronomy"
] | 435 | [
"Gemini (constellation)",
"Constellations"
] |
76,826,874 | https://en.wikipedia.org/wiki/Notebook%20%28laptop%29 | A notebook computer or notebook is, historically, a laptop whose length and width approximate that of letter paper ().
The term notebook was coined to describe slab-like portable computers that had a letter-paper footprint, such as Epson's HX-20 and Tandy's TRS-80 Model 100 of the early 1980s. The popularity of this form factor waned in the middle of the decade, as larger, clamshell-style laptops offered far more capability. In 1988, NEC's UltraLite defined a new category of notebook: it achieved IBM PC compatibility, making it technically as versatile as the largest laptops, while occupying a letter-paper footprint in a clamshell case. A handful of computer manufacturers followed suit with their own notebooks, including Compaq, whose successful LTE achieved full feature parity with laptops and spurred many others to produce their own notebooks. By 1991, the notebook industry was in full swing.
Notebooks and laptops occupied distinct market segments into the mid-1990s, but customer preference for larger screens led to notebooks converging with laptops in the late 1990s. Since the early 2000s, the terms laptop and notebook are used interchangeably, irrespective of physical dimensions, with laptop being the more common term in English-speaking territories.
Etymology
The terms laptop and notebook both trace their origins to the early 1980s, coined to describe portable computers in a size class smaller than the contemporary mainstream units (so-called "luggables") but larger than pocket computers. The etymologist William Safire traced the origin of laptop to some time before 1984; the earliest attestation of laptop found by the Oxford English Dictionary dates to 1983. The word is modeled after the term desktop, as in desktop computer. Notebook, meanwhile, emerged earlier in 1982 to describe Epson's HX-20 portable, whose dimensions roughly correspond to a letter-sized pad of paper.
History
In the mid-1980s, notebooks and laptops came to represent differing form factors of portable computer in the technology press, with notebooks possessing simplified hardware and a slab-like appearance with exposed keyboard (typified by the HX-20 and the TRS-80 Model 100); and laptops possessing more advanced hardware and a clamshell case to protect the keyboard. These early notebooks were all but discontinued by 1987, with laptops gaining favor due to their increased versatility.
By this point, however, laptops were gaining hardware features faster than the industry could miniaturize their parts, leading to very heavy laptops—some upwards of . In October 1988, NEC released the UltraLite, the first notebook-sized clamshell laptop compatible with the IBM PC. The term notebook was promptly revived by journalists to describe the new class of laptop that the UltraLite had invented. Competitors soon came out with competing models, and while initial entries like the UltraLite made concessions in terms of data storage compatibility, Compaq's LTE line of notebooks in 1989 was the first to have full feature parity with the heaviest laptops of the time and jumpstarted the industry for these new notebooks, with scores of other manufacturers announcing their own notebooks. Toshiba in 1989 released the DynaBook in Japan, the "world's first A4 binder size" notebook computer.
In direct response to Compaq, both Apple and IBM, top players in the computer industry, made their hotly anticipated entries in the notebook market in 1991 and 1992, respectively, with the PowerBook and the PS/2 Note (a predecessor to the ThinkPad). Under the aegis of the Industrial Technology Research Institute, dozens of Taiwanese computer manufacturers formed a consortium to mass manufacture notebook computers starting in 1991. These Taiwanese notebook computers soon flooded the West, bringing the cost of notebooks down on the low end of the market.
Laptops and notebooks continued to occupy discrete market segments into the mid-1990s, with unit sales tracked separately by research firms such as Dataquest. Notebooks were seen as having a footprint exactly that of or smaller than letter paper (), while laptops were larger. This distinction was considered important to business buyers, whose attaché cases often had a compartment exactly that size. An additional distinction was weight, with a loose upper limit for what journalists would accept as a "notebook" in the press. Aside from size and weight considerations, notebooks were also seen as more sleek and stylish than the bulkier laptops. Compared to notebooks, however, laptops saw quicker improvements in processing speed and memory; featured better upgradability; and were less easy to steal. In addition, the earliest notebooks had monochrome-only LCDs, whereas laptops had color LCDs since 1989 (with NEC's ProSpeed CSX). Others still preferred laptops for their keyboards, which featured fuller-sized layouts and often superior build quality; journalists evaluated the keyboard poorly in most early notebooks.
The year 1991 saw the first notebooks with color displays, as well as the emergence of subnotebooks, which occupy a size class in between notebooks and palmtop PCs. By late 1992, the higher-end notebooks had run into the same miniaturization issues that laptops had encountered in the 1980s, with some notebooks weighing as much as .
Starting in 1997, screen sizes in notebook computers began increasing rapidly, fueled by consumer preference toward larger displays over compactness. The emergence of LCD panels larger than 12.1 inches diagonally in early 1997 led to the breaking of the 8.5-by-11-inch size barrier. By 1999, portable manufacturers had started integrating 13-, 14-, and even 15-inch LCD panels on their notebooks. Ergonomic considerations, as well the integration of pointing devices such as touchpads, also necessitated increasing the size of laptops to accommodate a larger palm rest area. These developments led to the distinction between and laptops and notebooks becoming blurred by the early 2000s. In English-speaking territories, laptop is now the more common term to describe any clamshell portable computer—notebook-sized or otherwise—likely because of the lack of ambiguity with actual paper notebooks.
See also
Dynabook
Netbook
Smartbook
Ultrabook
Mobile workstation
Pizza-box form factor
Explanatory notes
References
External links
"Notebooks" (1992), episode of Computer Chronicles at the Internet Archive
Laptops
Mobile computers
Classes of computers | Notebook (laptop) | [
"Technology"
] | 1,326 | [
"Classes of computers",
"Computers",
"Computer systems"
] |
76,826,892 | https://en.wikipedia.org/wiki/HD%2037320 | HD 37320 (HR 1920, HIP 26487) is a star located in the constellation Orion. It is an evolved blue giant star, based on its spectral type of B8III. The distance to HD 37320 is calculated at , based on a parallax from Gaia EDR3. The apparent magnitude of the star is 5.852, which is above the limiting magnitude for naked-eye vision (6.5m), making it faintly visible to the naked eye.
Characteristics
It is an evolved blue giant star with a spectral type of B8III. It radiates about 219 times the solar luminosity by its photosphere at an effective temperature of 12,300 K. Its uniform disk angular diameter is measured at 0.153milliarcseconds. At the estimated distance by Gaia EDR3, it yields a physical size of . The star has a mass of and rotates under its own axis at a speed of 25 km/s.
HD 37320 is located within the constellation Orion, based on its astronomical coordinates. The distance to the star is , based on a parallax of from Gaia EDR3. The apparent magnitude of the star, i.e. its brightness as seen from Earth, is of 5.852m, which is above the limiting magnitude for naked-eye vision, generally defined as 6.5m, making it faintly visible to the naked eye. The absolute magnitude of HD 37320, i.e. its brightness if it was seen at , is -1.43. It is moving away from Earth at a velocity of 20.1 km/s.
HD 37320 is the Henry Draper Catalogue designation for this star. Other designations include HR 1920 from the Bright Star Catalogue, HIP 26487 from the Hipparcos Catalogue and BD+07 953 from the Bonner Durchmusterung catalogue.
Notes
References
Orion (constellation)
B-type giants
1920
026487
037320
2MASS objects | HD 37320 | [
"Astronomy"
] | 420 | [
"Constellations",
"Orion (constellation)"
] |
72,395,982 | https://en.wikipedia.org/wiki/KIF25 | Kinesin family member 25 (KIF25), also known as kinesin-14, is a human protein encoded by the KIF25 gene. It is part of the kinesin family of motor proteins.
Function
KIF25 is a minus-end directed microtubule motor protein, and its activity delays the separation of chromosomes during mitosis.
References | KIF25 | [
"Chemistry"
] | 77 | [
"Biochemistry stubs",
"Protein stubs"
] |
72,396,106 | https://en.wikipedia.org/wiki/KIF27 | Kinesin family member 27 (KIF27), also known as kinesin-4, is a human protein encoded by the KIF27 gene. It is part of the kinesin family of motor proteins.
References | KIF27 | [
"Chemistry"
] | 49 | [
"Biochemistry stubs",
"Protein stubs"
] |
72,396,541 | https://en.wikipedia.org/wiki/Antilimit | In mathematics, the antilimit is the equivalent of a limit for a divergent series. The concept not necessarily unique or well-defined, but the general idea is to find a formula for a series and then evaluate it outside its radius of convergence.
Common divergent series
See also
Abel summation
Cesàro summation
Lindelöf summation
Euler summation
Borel summation
Mittag-Leffler summation
Lambert summation
Euler–Boole summation and Van Wijngaarden transformation can also be used on divergent series
References
Divergent series
Summability methods
Sequences and series
Mathematical analysis | Antilimit | [
"Mathematics"
] | 125 | [
"Sequences and series",
"Mathematical analysis",
"Mathematical structures",
"Mathematical analysis stubs",
"Summability methods",
"Mathematical objects"
] |
72,398,077 | https://en.wikipedia.org/wiki/Pisolithus%20marmoratus | Pisolithus marmoratus is a species of gasteroid fungus.
Description
Appears as a roughly spherical fruiting-body mottled with shades of black, brown and gold and with a rough surface texture. Like other Pisolithus species it is sometimes described as resembling horse dung.
P. marmoratus has been sighted across the world in association with plants in the Myrtaceae family. It is native to Australia.
References
Fungi described in 1900
Fungi of Australia
Fungus species
Pisolithus | Pisolithus marmoratus | [
"Biology"
] | 104 | [
"Fungi",
"Fungus species"
] |
72,398,441 | https://en.wikipedia.org/wiki/Abrothallus%20boomii | Abrothallus boomii is a species of lichenicolous fungus in the family Abrothallaceae. Found in Portugal, it was formally described as a new species in 2015 by Ave Suija and Sergio Pérez-Ortega. The type specimen was collected north of (Beira Alta Province) in a pine-oak forest along a vineyard, where it was found growing on the thallus of a Nephroma lichen. It is only known to occur at the type locality. The species epithet honours Dutch lichenologist Pieter van den Boom, "author of a long list of research articles and indefatigable collector of lichens and lichenicolous fungi".
Compared to other Abrothallus fungi that grow on Nephroma, Abrothallus boomii differs in that its asci contain six spores, its are semi-immersed, and its hyaline typically measure 7–10.5 by 5.5–8 μm.
References
boomii
Lichenicolous fungi
Fungi described in 2015
Fungi of Europe
Taxa named by Ave Suija
Fungus species | Abrothallus boomii | [
"Biology"
] | 224 | [
"Fungi",
"Fungus species"
] |
72,398,473 | https://en.wikipedia.org/wiki/Abrothallus%20canariensis | Abrothallus canariensis is a species of lichenicolous fungus in the family Abrothallaceae. Found in the Canary Islands, it was formally described as a new species in 2015 by Sergio Pérez-Ortega, Pieter van den Boom, and Ave Suija. The type specimen was collected from Chinobre (Santa Cruz de Tenerife), where it was found on a Pseudocyphellaria aurata lichen that itself was growing on a species of Erica. The species epithet refers to the area of its type locality. The fungus is similar to Abrothallus secedens, but unlike that species, has four-spored asci, and larger ascospores that measure 16–25 by 6–9.5 μm.
References
canariensis
Lichenicolous fungi
Fungi described in 2015
Fungi of the Canary Islands
Taxa named by Ave Suija
Fungus species | Abrothallus canariensis | [
"Biology"
] | 185 | [
"Fungi",
"Fungus species"
] |
72,398,492 | https://en.wikipedia.org/wiki/Abrothallus%20doliiformis | Abrothallus doliiformis is a species of lichenicolous fungus in the family Abrothallaceae. Found in Peru, it was formally described as a new species in 2015 by Ave Suija and Sergio Pérez-Ortega. The type specimen was collected from Machu Picchu (Department of Cuzco) at an elevation of , where it was growing on the thallus of an unidentified Sticta lichen. It is only known to occur at the type locality. The species epithet doliiformis refers to its doliiform (barrel-shaped) . This feature, along with its hyaline, single-celled conidia (measuring 9.5–14.5 by 6–9.5 μm) distinguish it from other Abrothallus fungi.
References
doliiformis
Lichenicolous fungi
Fungi described in 2015
Fungi of South America
Taxa named by Ave Suija
Fungus species | Abrothallus doliiformis | [
"Biology"
] | 190 | [
"Fungi",
"Fungus species"
] |
72,398,561 | https://en.wikipedia.org/wiki/Abrothallus%20eriodermae | Abrothallus eriodermae is a species of lichenicolous fungus in the family Abrothallaceae. Found in Alaska, South America, Jamaica, and Réunion island, it was formally described as a new species in 2015 by Ave Suija, Javier Etayo, and Sergio Pérez-Ortega. The type specimen was collected from the Bébour forest in La Reunion, growing on Erioderma papyraceum. It has also been recorded on Erioderma chilense, E. sorediatum, and E. wrightii. The species epithet refers to the host genus Erioderma.
References
eriodermae
Lichenicolous fungi
Fungi described in 2015
Fungi of North America
Fungi of South America
Fungi of Réunion
Fungi of the Caribbean
Taxa named by Javier Angel Etayo Salazar
Taxa named by Ave Suija
Fungus species | Abrothallus eriodermae | [
"Biology"
] | 175 | [
"Fungi",
"Fungus species"
] |
72,398,642 | https://en.wikipedia.org/wiki/Abrothallus%20ertzii | Abrothallus ertzii is a species of lichenicolous fungus in the family Abrothallaceae. Found in Canada, it was formally described as a new species in 2015 by Ave Suija and Sergio Pérez-Ortega. The type specimen was collected near Dawson Falls in Wells Gray Provincial Park (British Columbia), where it was found growing on the thallus of the foliose lichen Lobaria pulmonaria, which itself was growing on the trunk of a Thuja plicata tree. It has also been collected in Quebec. The species epithet honours Damien Ertz, who collected the type. Abrothallus ertzii is distinguished from other Abrothallus fungi by its clavate (club-shaped) asci that contain eight two-celled ascospores; these readily split into part spores.
References
ertzii
Lichenicolous fungi
Fungi described in 2015
Fungi of Canada
Taxa named by Ave Suija
Fungus species | Abrothallus ertzii | [
"Biology"
] | 201 | [
"Fungi",
"Fungus species"
] |
72,398,699 | https://en.wikipedia.org/wiki/Abrothallus%20etayoi | Abrothallus etayoi is a species of lichenicolous fungus in the family Abrothallaceae. Found in Mexico, it was formally described as a new species in 2015 by Ave Suija and Sergio Pérez-Ortega. The type specimen was collected from Angahuan (Michoacán) at an elevation of ; there, in a pine-oak forest, it was found growing on a Sticta lichen that itself was growing on oak. The species epithet honours Spanish lichenologist Javier Etayo, "a keen collector of lichenicolous fungi and lichens".
Abrothallus etayoi differs from other Abrothallus fungi by the shape of its (barrel-shaped to somewhat spherical), and by its single-celled conidia that measure 11–17.5 by 7–11 μm. Although known only from the type locality, the authors suggest that the fungus may have a wider distribution in Mexico due to the prevalence of the ecosystem from which it was collected.
References
etayoi
Lichenicolous fungi
Fungi described in 2015
Fungi of Mexico
Taxa named by Ave Suija
Fungus species | Abrothallus etayoi | [
"Biology"
] | 235 | [
"Fungi",
"Fungus species"
] |
72,399,164 | https://en.wikipedia.org/wiki/Abrothallus%20nephromatis | Abrothallus nephromatis is a widely distributed species of lichenicolous fungus in the family Abrothallaceae. It was formally described as a new species in 2015 by Ave Suija and Sergio Pérez-Ortega. The type specimen was collected near Dawson Falls in Wells Gray Provincial Park (British Columbia, Canada) at an elevation of about , where it was found on a Nephroma parile lichen that itself was growing on a dead trunk of birch tree. The species epithet refers to the host genus, Nephroma.
Abrothallus nephromatis has been collected from Africa (Tanzania, Uganda); Asia (Russian Far East); Australia and New Zealand; Europe (Italy, Norway, Sweden), Greenland, and North America (Canada, USA). It is distinguished from the similar species Abrothallus boomii by its eight-spored asci and narrower conidia, and from Abrothallus welwitschii by its smaller ascomata and smaller ascospores. The recorded hosts of the fungus are Nephroma parile, N. helveticum, N. rufum, and N. tropicum.
References
nephromatis
Lichenicolous fungi
Fungi described in 2015
Fungi of Asia
Fungi of Africa
Fungi of Australia
Fungi of Greenland
Fungi of New Zealand
Fungi of Europe
Taxa named by Ave Suija
Fungus species | Abrothallus nephromatis | [
"Biology"
] | 294 | [
"Fungi",
"Fungus species"
] |
72,399,552 | https://en.wikipedia.org/wiki/Abrothallus%20granulatae | Abrothallus granulatae is a species of lichenicolous fungus in the family Abrothallaceae. Found in South America, it was formally described as a new species in 1994 by Swedish lichenologist Mats Wedin. The type specimen was collected by the author on the eastern shore of Lago Roca in Tierra del Fuego National Park (Patagonia, Argentina), where it was found on the thallus of the foliose lichen Pseudocyphellaria granulata, which itself was growing on the base of a dead Nothofagus tree. The species epithet of the fungus refers to the epithet of its host lichen. The anamorph form of the fungus was concurrently named Vouauxiomyces granulatae. Characteristics of the fungus include the dense clusters formed by its apothecia, and its 2-septate ascospores. Abrothallus granulatae has also been collected in Chile.
References
granulatae
Fungi described in 1994
Fungi of South America
Lichenicolous fungi
Taxa named by Mats Wedin
Fungus species | Abrothallus granulatae | [
"Biology"
] | 226 | [
"Fungi",
"Fungus species"
] |
72,399,627 | https://en.wikipedia.org/wiki/S-%282-Aminoethyl%29isothiuronium%20bromide%20hydrobromide | S-(2-Aminoethyl)isothiourea dihydrobromide, commonly knwn as AET, is a isothiouronium-group-containing reducing agent with textbook uses as a disulfide reducing agent. Though it does not have a free thiol group (-SH) like 2-mercaptoethanol and dithiothreitol (DTT), it reacts with water to decompose transiently into thiol intermediates that acts on disulfide in a manner to these containing free -SH groups.
Applications
One application of AET is in hematology where red cells are treated with AET to create PNH-like cells.
References
Reducing agents
Thioureas | S-(2-Aminoethyl)isothiuronium bromide hydrobromide | [
"Chemistry"
] | 153 | [
"Redox",
"Reducing agents"
] |
72,399,684 | https://en.wikipedia.org/wiki/Abrothallus%20secedens | Abrothallus secedens is a species of lichenicolous fungus in the family Abrothallaceae. Found in Africa, South America, and the United States, it was formally described as a new species in 1994 by Swedish lichenologists Mats Wedin and Rolf Santesson. The type specimen was collected by the first author on the Martial Glacier in Ushuaia (Tierra del Fuego, Argentina) at an altitude of , where it was found on the thallus of the foliose lichen Pseudocyphellaria dubia, which itself was growing on the base of a Nothofagus antarctica tree. It has also been collected in Chile, Kenya, and Alaska. The species epithet of the fungus, secedens ("splitting apart") refers to the two-celled ascospores that eventually separate into single-celled part spores. Known hosts for Abrothallus secedens include Crocodia aurata, Pseudocyphellaria dubia, P. mallota, P. obvoluta, and other Pseudocyphellaria lichens not identified to species.
References
secedens
Fungi described in 1994
Fungi of Africa
Fungi of South America
Fungi of the United States
Lichenicolous fungi
Taxa named by Rolf Santesson
Fungus species | Abrothallus secedens | [
"Biology"
] | 269 | [
"Fungi",
"Fungus species"
] |
72,399,809 | https://en.wikipedia.org/wiki/Abrothallus%20halei | Abrothallus halei is a species of lichenicolous fungus in the family Abrothallaceae. It was formally described as a new species in 2010 by lichenologists Sergio Pérez-Ortega, Ave Suija, David Leslie Hawksworth, and Rolf Santesson. The type specimen was collected by Cliff Wetmore east of Hare Lake (Superior National Forest, Minnesota) at an elevation of ; there it was found on the foliose lichen Lobaria quercizans, which itself was growing on the bark of Acer saccharum. The fungus has also been collected in West Virginia, Maine, as well as in Norway. The species epithet honours American lichenologist Mason Hale.
References
halei
Fungi described in 2010
Fungi of Europe
Fungi of the United States
Taxa named by David Leslie Hawksworth
Taxa named by Rolf Santesson
Taxa named by Ave Suija
Fungus species
Lichenicolous fungi | Abrothallus halei | [
"Biology"
] | 188 | [
"Fungi",
"Fungus species"
] |
72,400,763 | https://en.wikipedia.org/wiki/Capronia%20suijae | Capronia suijae is a species of lichenicolous fungus in the family Herpotrichiellaceae. Found in Belarus, it was formally described as a new species in 2017 by Andrei Tsurykau and Javier Etayo. The type specimen was collected from Ostrozhanka Village (Lyelchytsy District) where it was found growing on the thallus of the bark-dwelling, crustose lichen Xanthoria parietina; Muellerella lichenicola was also simultaneously parasitizing the lichen. Capronia suijae is only known to occur at the type locality. The species epithet suijae honours Estonian lichenologist Ave Suija, "in recognition of her important contribution to the knowledge of lichenicolous fungi".
References
Eurotiomycetes
Fungi described in 2017
Lichenicolous fungi
Fungi of Europe
Taxa named by Javier Angel Etayo Salazar
Fungus species | Capronia suijae | [
"Biology"
] | 190 | [
"Fungi",
"Fungus species"
] |
72,402,123 | https://en.wikipedia.org/wiki/Olutasidenib | Olutasidenib, sold under the brand name Rezlidhia, is an anticancer medication used to treat relapsed or refractory acute myeloid leukemia with a susceptible IDH1 mutation. Olutasidenib is an isocitrate dehydrogenase-1 (IDH1) inhibitor. It is taken by mouth.
The most common adverse reactions include nausea, fatigue/malaise, arthralgia, constipation, leukocytosis, dyspnea, fever, rash, mucositis, diarrhea, and transaminitis.
Olutasidenib was approved for medical use in the United States in December 2022, based on the phase 1 results of a phase 1/2 trial.
Medical uses
Olutasidenib is indicated for the treatment of adults with relapsed or refractory acute myeloid leukemia with a susceptible isocitrate dehydrogenase-1 (IDH1) mutation as detected by an FDA-approved test.
Society and culture
Names
Olutasidenib is the international nonproprietary name.
References
Further reading
External links
Antineoplastic drugs
Orphan drugs
Nitriles
2-Pyridones
Chloroarenes
2-Quinolones | Olutasidenib | [
"Chemistry"
] | 268 | [
"Nitriles",
"Functional groups"
] |
72,402,167 | https://en.wikipedia.org/wiki/Axial%20parallelism | Axial parallelism (also called gyroscopic stiffness, inertia or rigidity, or "rigidity in space") is the characteristic of a rotating body in which the direction of the axis of rotation remains fixed as the object moves through space. In astronomy, this characteristic is found in astronomical bodies in orbit. It is the same effect that causes a gyroscope's axis of rotation to remain constant as Earth rotates, allowing the devices to measure Earth's rotation.
Examples
Earth's axial parallelism
The Earth's orbit, with its axis tilted at 23.5 degrees, exhibits approximate axial parallelism, maintaining its direction towards Polaris (the "North Star") year-round. Together with the Earth's axial tilt, this is one of the primary reasons for the Earth's seasons, as illustrated by the diagram to the right. It is also the reason that the stars appear fixed in the night sky, such as a "fixed" pole star, throughout Earth's orbit around the Sun.
Minor variation in the direction of the axis, known as axial precession, takes place over the course of 26,000 years. As a result, over the next 11,000 years the Earth's axis will move to point towards Vega instead of Polaris.
Other astronomical examples
Axial parallelism is widely observed in astronomy. For example, the axial parallelism of the Moon's orbital plane is a key factor in the phenomenon of eclipses. The Moon's orbital axis precesses a full circle during the 18 year, 10 day saros cycle. When the Moon's orbital tilt is aligned with the ecliptic tilt, it is 29 degrees from the ecliptic, while when they are anti-aligned (9 years later), the orbital inclination is only 18 degrees.
In addition, the rings of Saturn remain in a fixed direction as that planet rotates around the Sun.
Explanation
Early gyroscopes were used to demonstrate the principle, most notably the Foucault's gyroscope experiment. Prior to the invention of the gyroscope, it had been explained by scientists in various ways. Early modern astronomer David Gregory, a contemporary of Isaac Newton, wrote:
To explain the Motion of the Celestial Bodies about their proper Axes, given in Position, and the Revolutions of them… If a Body be said to be moved about a given Axe, being in other respects not moved, that Axe is suppos'd to be unmov'd, and every point out of it to describe a Circle, to whose Plane the Axis is perpendicular. And for that reason, if a Body be carried along a line, and at the same time be revolved about a given Axe; the Axe, in all the time of the Body's motion, will continue parallel to it self. Nor is any thing else required to preserve this Parallelism, than that no other Motion besides these two be impressed upon the Body; for if there be no other third Motion in it, its Axe will continue always parallel to the Right-line, to which it was once parallel.
This gyroscopic effect is described in modern times as "gyroscopic stiffness" or "rigidity in space". The Newtonian mechanical explanation is known as the conservation of angular momentum.
See also
Axial tilt
Polar motion
Rotation around a fixed axis
True polar wander
References
Technical factors of astrology
Celestial mechanics | Axial parallelism | [
"Physics"
] | 706 | [
"Celestial mechanics",
"Classical mechanics",
"Astrophysics"
] |
72,403,854 | https://en.wikipedia.org/wiki/Austin-Rover%20V64V%20engine | The V64V engine was a purpose-built and specially made naturally-aspirated DOHC V6 engine, designed, developed and produced by Austin-Rover, for the MG Metro 6R4 Group B rally car, between 1985 and 1986.
Applications
MG Metro 6R4
References
Automobile engines
Internal combustion piston engines
V6 engines
Gasoline engines by model
Engines by model
Rover engines | Austin-Rover V64V engine | [
"Technology"
] | 76 | [
"Automobile engines",
"Engines",
"Engines by model"
] |
72,405,181 | https://en.wikipedia.org/wiki/Mahesh%20Kakde | Mahesh Ramesh Kakde (born 1983) is a mathematician working in algebraic number theory.
Biography
Mahesh Kakde was born on 1983 in Akola, India. He obtained a Bachelor of Mathematics degree at the Indian Statistical Institute in Bangalore in 2004, and a Certificate of Advanced Study in Mathematics at the University of Cambridge in 2005. He completed his PhD under the supervision of John Coates at the University of Cambridge in 2008. He subsequently worked at Princeton University, University College London, and King's College London, before becoming a professor at the Indian Institute of Science in 2019.
Research
Kakde proved the main conjecture of Iwasawa theory in the totally real case. Together with Samit Dasgupta and Kevin Ventullo, he proved the Gross–Stark conjecture. In a joint project with Samit Dasgupta, they proved the Brumer–Stark conjecture away from 2 in 2020, and later over in 2023. Generalising these methods, they also gave a solution to Hilbert's 12th problem for totally real fields. Their methods were subsequently used by Johnston and Nickel to prove the equivariant Iwasawa main conjecture for abelian extensions without the hypothesis.
Awards
In 2019, Kakde was awarded a Swarnajayanti Fellowship.
Together with Samit Dasgupta, Kakde was one of the invited speakers at the International Congress of Mathematicians 2022, where they gave a joint talk on their work on the Brumer–Stark conjecture.
In 2022, Kakde received the Infosys Prize for his contributions to algebraic number theory. In his congratulatory message, Jury Chair Chandrashekhar Khare noted that "[Kakde’s] work on the main conjecture of non-commutative Iwasawa theory, on the Gross-Stark conjecture and on the Brumer-Stark conjecture has had a big impact on the field of algebraic number theory. His work makes important progress towards a p-adic analytic analog of Hilbert’s 12th problem on construction of abelian extensions of number fields."
References
External links
Old official website at King's College London
21st-century Indian mathematicians
Academic staff of the Indian Institute of Science
1983 births
Number theorists
People from Akola
Alumni of the University of Cambridge
Indian Statistical Institute alumni
Living people | Mahesh Kakde | [
"Mathematics"
] | 476 | [
"Number theorists",
"Number theory"
] |
72,405,534 | https://en.wikipedia.org/wiki/Extended%20peer%20community | The concept of Extended peer community belongs to the field of Sociology of science, and in particular the use of science in the solution of social, political or ecological problems. It was first introduced by in the 1990s by Silvio Funtowicz and Jerome R. Ravetz. in the context of what would become Post-normal science.
An Extended peer community is intended by these authors as a space where both credentialed experts from different disciplines and lay stakeholders can discuss and deliberate.
Content
An Extended peer community is intended by its creators as an arrangement at the science policy interface that helps to expand and assess both the knowledge-base and the value-base of policy-making'.
Post-normal science's extended peer community argues for two kind of extensions: first, more than one discipline is assumed to have a potential bearing on the issue being debated, thereby providing different lenses to consider the problem. Second the community is extended to lay actors, taken to be all those with stakes, or an interest, in the given issue.
The lay members of the community thus constituted may also take upon themselves active 'research' tasks; this has happened e.g. in the so-called 'popular epidemiology', when the official authorities have shown reluctance to perform investigations deemed necessary by the communities affected - for example - by a case of air or water pollution, and more recently ‘citizen science’. The extended community can usefully investigate the quality of the scientific assessments provided by the experts, the definition of the problem, as well as research priorities and research questions.
An example of extended peer community in action is offered by Brian Wynne, who discusses the Cumbrian sheep farmers' interaction with scientists and authorities, mobilizing farmers' knowledge of the relevant situation (acid upland moors retaining radioactive deposition from fallout longer than the lowland Oxfordshire meadows on which the official parameters were based).
Extended peer communities and Post-normal Science have been suggested to tackle the debate on the policy and regulation of Large Language Models in order to encourage "inclusion of previously marginalised perspectives".
The concept of extended peer community was developed in the context of politicised quality controversies in science (such as 'housewife' or 'popular' epidemiology ), early evidence-based medicine (the Cochrane collaboration), and the total quality management ideas of W. Edwards Deming, in particular quality circles. EPC is discussed in a special issue of the journal Science, Technology, & Human Values. For Eugene A. Rosa EPC can help charting "extended facts", meant as local knowledge, understanding, and non academic sources.
See also
Post-normal science
Sociology of scientific knowledge
Technology and society
Science studies
Social construction of technology
References
Scientific method
Philosophy of science
Science and technology studies | Extended peer community | [
"Technology"
] | 556 | [
"Science and technology studies"
] |
72,405,611 | https://en.wikipedia.org/wiki/Opel%20DTM%20V8%20engine | The Opel DTM V8 engine family is a series of prototype, four-stroke, 4.0-liter, naturally aspirated DOHC V-8 racing engines, designed, developed and produced by Opel, and specially tuned by German manufacturer Spiess, for the Deutsche Tourenwagen Meisterschaft, between 2000 and 2005.
Applications
Opel Astra DTM
Opel Vectra GTS V8 DTM
References
V8 engines
Opel engines
Gasoline engines by model
Engines by model
Piston engines
Internal combustion engine | Opel DTM V8 engine | [
"Technology",
"Engineering"
] | 107 | [
"Internal combustion engine",
"Engines",
"Engines by model",
"Piston engines",
"Combustion engineering"
] |
72,406,120 | https://en.wikipedia.org/wiki/Foucault%27s%20gyroscope | The Foucault gyroscope was a gyroscope created by French physicist Léon Foucault in 1852, conceived as a follow-up experiment to his pendulum in order to further demonstrate the Earth's rotation.
Foucault felt that the results of his famous pendulum experiment had been misunderstood. He therefore endeavored to create an apparatus with a "body freely suspended by its center of gravity and rotating around one of its principal axes", allowing the study of a plane with "absolute directional stability". The mechanical precision of Foucault's gyroscope allowed this to be proven clearly to the scientific establishment, and the gyroscope became a widely popular instrument.
Design
Together with Paul-Gustave Froment, Foucault built an apparatus in which the inner gimbal was balanced on knife edge bearings on the outer gimbal and the outer gimbal was suspended by a fine, torsion-free thread in such a manner that the lower pivot point carried almost no weight.
The gyro was spun to 9,000–12,000 revolutions per minute with an arrangement of gears before being placed into position, which was sufficient time to balance the gyroscope and carry out 10 minutes of experimentation. The instrument could be observed either with a microscope viewing a tenth of a degree scale or by a long pointer.
Publications
Foucault published two papers in 1852, one focused on astronomy with the weight free to move on all three axes (On a new experimental demonstration of the motion of the Earth, based on the fixity of the plane of rotation) and the other on mechanics with the weight free to move on only two axes (On the orientation phenomena of rotating bodies driven by a fixed axis on the Earth's surface. New sensitive signs of daily movement).
In the paper on mechanics, Foucault explained that if one axis of rotation is fixed in line with the surface of the Earth, the other two axes of rotation tend to the same direction, similar to "a magnetic needle", making it possible to use the instrument to highlight a directing force.
Naming
Foucault coined the name "gyroscope" in the 1852 publication of his experiment:
This apparatus specially designed to highlight and approximate the deviation of a freely rotating body can also be used to produce and observe the phenomena of orientation that I have just stated and described. As all these phenomena depend on the movement of the Earth and are its varied manifestations, I propose to name the sole instrument which has served me to observe them gyroscope.
Copies
At least three more copies of a Foucault's gyroscope were made in convenient travelling and demonstration boxes, and copies survive in the UK, France, and the US. The original was given to the Collège de France and was lost, there are no known photographs of the original suggesting it was lost a few decades after the College received it.
The Foucault gyroscope became a challenge and source of inspiration for skilled science hobbyists such as David B. Adamson.
Gallery
Citations
References
Gyroscopes
Physics experiments
French inventions | Foucault's gyroscope | [
"Physics"
] | 644 | [
"Experimental physics",
"Physics experiments"
] |
72,406,363 | https://en.wikipedia.org/wiki/Gurzadyan%20theorem | In cosmology, the Gurzadyan theorem, proved by Vahe Gurzadyan, states the most general functional form for the force satisfying the condition of identity of the gravity of the sphere and of a point mass located in the sphere's center. This theorem thus refers to the first statement of Isaac Newton’s shell theorem (the identity mentioned above) but not the second one, namely, the absence of gravitational force inside a shell.
The theorem had entered and its importance for cosmology outlined in several papers as well as in shell theorem.
The formula and the cosmological constant
The formula for the force derived in has the form
where and are constants. The first term is the familiar law of universal gravitation, the second one corresponds to the cosmological constant term in general relativity and McCrea-Milne cosmology.
Then the field is force-free only in the center of a shell but the confinement (oscillator) term does not change the initial symmetry of the Newtonian field. Also, this field corresponds to the only field possessing the property of the Newtonian one: the closing of orbits at any negative value of energy, i.e. the coincidence of the period of variation of the value of the radius vector with that of its revolution by (resonance principle) .
Consequences: cosmological constant as a physical constant
Einstein named the cosmological constant as a universal constant, introducing it to define the static cosmological model. Einstein has stated: “I should have initially set in Newton's sense. But the new considerations speak for a non-zero , which strives to bring about a non-zero mean density of matter.” This theorem solves that contradiction between “non-zero ” and Newton's law.
From this theorem the cosmological constant emerges as additional constant of gravity along with the Newton's gravitational constant . Then, the cosmological constant is dimension independent and matter-uncoupled and hence can be considered even more universal than Newton's gravitational constant.
For joining the set of fundamental constants , the gravitational
Newton's constant, the speed of light and the Planck constant, yields
and a dimensionless quantity emerges for the 4-constant set
where is a real number. Note, no dimensionless quantity is possible to construct from the 3 constants .
This within a numerical factor, , coincides with the information (or entropy) of de Sitter event horizon
and the Bekenstein Bound
Rescaling of physical constants
Within the Conformal Cyclic Cosmology this theorem implies that, in each aeon of an initial value of , the values of the 3 physical constants will be eligible for rescaling fulfilling the dimensionless ratio of invariants with respect to the conformal transformation
Then the ratio yields
for all physical quantities in Planck (initial) and de Sitter (final) eras of the aeons, remaining invariant under conformal transformations.
Inhomogeneous Fredholm equation
This theorem, in the context of nonlocal effects in a system of gravitating particles, leads to the inhomogeneous Dirichlet boundary problem for the Poisson equation
where is the radius of the region,
.
Its solution can be expressed in terms of the double layer potential, which leads to an inhomogeneous nonlinear Hammerstein integral equation for the gravitational potential
This leads to a linear inhomogeneous 2nd kind Fredholm equation
Its solution can be expressed in terms of the resolvent of the integral kernel and the non-linear (repulsive) term
Observational indications
The dynamics of groups and clusters of galaxies are claimed to fit the theorem, see also.
The possibility of two Hubble flows, a local one, determined by that formula, and a global one, described by Friedmannian cosmological equations was stated in.
References
Eponymous theorems of physics
Gravity
Mathematical theorems | Gurzadyan theorem | [
"Physics",
"Mathematics"
] | 788 | [
"Equations of physics",
"Eponymous theorems of physics",
"nan",
"Mathematical problems",
"Mathematical theorems",
"Physics theorems"
] |
72,407,088 | https://en.wikipedia.org/wiki/Connie%20Woodhouse | Connie A. Woodhouse is a regents professor at the University of Arizona who is known for her use of tree rings to reconstruct the hydroclimate of the past, especially in western North America. In 2022 she was elected a fellow of the American Geophysical Union
Education and career
Woodhouse has a B.A. from Prescott College (1979), an M.S. from the University of Utah (1989), and a Ph.D. from the University of Arizona (1996). Following her Ph.D., Woodhouse worked at the University of Colorado Boulder until 2007 when she moved to the University of Arizona as an associate professor. In 2013 she was named professor in the School of Geography and Development, and in 2020 she was named a regents professor.
Research
Woodhouse's early research examined the long-term variability in drought conditions in the United States. She has used dating with tree rings to examine the flow of water and snow levels in Colorado. Her research extends into considerations of air temperature, the efficiency of stream runoff, and flash droughts. Her work on droughts in the past has indicated the potential of Dust Bowl conditions in the future. Thus, her work on past climate has implication for the future impact of drought conditions
Selected publications
Awards and honors
In 2016, Woodhouse received the José A. Boninsegna Frontiers in Dendrochronology Award in recognition of her work in reconstructing past climates and for sharing this information with people who manage water resources. In 2022 Woodhouse was elected a fellow of the American Geophysical Union.
References
External links
Living people
Women climatologists
Prescott College alumni
University of Utah alumni
University of Arizona faculty
Hydrologists
Year of birth missing (living people) | Connie Woodhouse | [
"Environmental_science"
] | 352 | [
"Hydrology",
"Hydrologists"
] |
72,407,431 | https://en.wikipedia.org/wiki/TapTap | TapTap is a mobile game-sharing community and third-party game store that originated in China, operated by XD Inc. The platform allows users to download games and engage within the community.
In June 2022, TapTap reached an average of 9 million monthly active users from over 170 countries, including the United States, Japan, Germany, and Italy.
ByteDance, the parent company of TikTok, game developer miHoYo, and Lilith Mobile are investors of TapTap. In 2020, MiHoYo’s Genshin Impact was distributed on TapTap.
Exclusives
While with similarities to the offering on mainstream app stores such as Google Play and the App Store, TapTap holds exclusives to games such as Torchlight: Infinite and T3 Arena during alpha testing and Valorant Mobile.
Events
TapTap Presents
TapTap Presents is a Live Show, hosted by TapTap, that first streamed on July 10, 2020, unveiling game-related updates and upcoming mobile games, including Genshin Impact and Torchlight: Infinite.
History
TapTap was created by Yiwan in 2016 with an investment from XD Inc., previously known for peer-to-peer download network VeryCD. In March 2018, TapTap was fined for violating games publishing laws in China, among other companies, and shut down its service for 3 months.
References
External links
Mobile software distribution platforms | TapTap | [
"Technology"
] | 289 | [
"Mobile content",
"Mobile software distribution platforms"
] |
72,408,552 | https://en.wikipedia.org/wiki/Hyperpolarized%20gas%20MRI | Hyperpolarized gas MRI, also known as hyperpolarized helium-3 MRI or HPHe-3 MRI, is a medical imaging technique that uses hyperpolarized gases to improve the sensitivity and spatial resolution of magnetic resonance imaging (MRI). This technique has many potential applications in medicine, including the imaging of the lungs and other areas of the body with low tissue density.
The current standard for diagnosing and monitoring treatment of pulmonary diseases is spirometric pulmonary function testing (PFTs). However, these tests only assess the lung on a global basis and are generally not sensitive enough to detect functional changes in the small airways and gas exchange regions. This lack of sensitivity has led these regions to be known as the "silent zone." Additionally, PFT metrics largely rely on the effort of the subject, leading to significant measurement uncertainty and variability. As a result, current therapy is largely based on patients' symptoms and survival. Given the high burden on the healthcare system and the increasing prevalence of pulmonary disease, there is a need for improved diagnostic tools and quantitative metrics to better diagnose and quantify pulmonary disease progression and accurately measure response to therapy.
The basic principle of hyperpolarized gas MRI is similar to that of conventional MRI, which uses powerful magnetic fields and radio waves to create detailed images of the body's internal structures. In conventional MRI, the magnetic moments of hydrogen atoms (protons) in the body's water and fat molecules are aligned with the magnetic field and then subjected to a radiofrequency pulse. This causes the protons to absorb energy and become excited, and when the radiofrequency pulse is turned off, the protons relax and release their energy in the form of a detectable signal. This signal is used to construct an image of the body's tissues.
Overcoming challenges of traditional MRI
Traditional MR imaging of the lungs is difficult because conventional scanners are designed to excite hydrogen protons, which are present in water molecules. However, the lungs have only a very low density of hydrogen protons compared to other structures, and their long relaxation time means that the signal available for imaging is minimal. In addition, the inhomogeneous magnetic environment of the lungs introduces susceptibility artifacts that further complicate MR acquisitions. These challenges are not faced by external gaseous contrast media like 3He or 129Xe, which image the airways and airspaces within the lungs rather than the surrounding tissues. This greatly reduces the problems of unfavorable longitudinal and transverse relaxation times faced by hydrogen MRIs in the lung. However, MR imaging of a gas is challenging because its density is typically about 4 orders of magnitude lower than that of protons. To overcome this limitation, a process called hyperpolarization is used to increase the magnetization of these gases by about 5 orders of magnitude. This makes MR-based imaging of inhaled gases feasible within a single breath hold.
To improve the ability to detect early lung disease, it is necessary to use imaging techniques that provide regional information. Hyperpolarized gas magnetic resonance imaging (HP gas MRI) is a non-invasive, radiation-free method that can image the structure and function of the lungs. While 3He was originally used extensively in HP gas MRI, its recent scarcity and increase in price has led to a shift towards the cheaper and more abundant 129Xe. The advantage of using 129Xe is that it is soluble in pulmonary tissues, providing two additional signal sources in addition to the xenon in the airspaces. These three 129Xe resonances can provide quantitative regional information about the fundamental function of the lungs: gas exchange.
History and safety
In 1994, the first studies on hyperpolarized (HP) gas magnetic resonance imaging (MRI) were carried out using the noble gas isotope 129-Xenon (129Xe). In 1997, Mugler and colleagues used 129Xe to conduct the first studies in humans. However, these studies were limited by relatively low 129Xe polarizations (1-2%), which resulted in low signal intensities. This issue led to a shift in research interest to helium (3He), which has a larger gyromagnetic ratio than 129Xe and offers a simpler and more mature polarization technology (30%) and corresponding larger signal intensities. 3He also does not have any physiological side effects, making it a better starting point for clinical imaging.
In 1996, 3He MR imaging entered clinical research and expanded to multi-center clinical studies. The results of the ventilation studies showed a significant correlation to conventional pulmonary function tests in patients with chronic obstructive pulmonary disease, asthma, and cystic fibrosis. The main problem with 3He HP MR imaging is the limited supply of 3He, which comes from the decay of tritium, a byproduct of nuclear weapons production. This has driven up costs significantly to around $800–2000 per liter depending on academic versus commercial use. Due to these higher costs and lower availability, 3He HP MR imaging is not economically sustainable.
Recent advances in 129Xe polarization technology have led to the reintroduction of 129Xe MR imaging in humans. Xenon has a long history of safe use as a contrast agent in computed tomography lung imaging studies, which was confirmed in safety studies on inhaling hyperpolarized 129Xe. With the development of more efficient polarizers, resulting in improved 129Xe polarization, it is expected that better image quality can be achieved with a lower volume of xenon. A second safety study showed that inhalation of only 0.5-liter volumes caused subjects to experience few or no symptoms.
Physics of hyperpolarization
The basic principle of hyperpolarized gas MRI is similar to that of conventional MRI, which uses powerful magnetic fields and radio waves to create detailed images of the body's internal structures. In conventional MRI, the magnetic moments of hydrogen atoms (protons) in the body's water and fat molecules are aligned with the magnetic field and then subjected to a radiofrequency pulse. This causes the protons to absorb energy and become excited, and when the radiofrequency pulse is turned off, the protons relax and release their energy in the form of a detectable signal. This signal is used to construct an image of the body's tissues.
In hyperpolarized gas MRI, the gases used are noble gases, such as 3He or 129Xe, which have large nuclear magnetic moments but low natural abundance and therefore produce very weak signals. To increase the nuclear spin polarization of either 3He or 129Xe, two processes are involved: 1) optical pumping and 2) spin exchange.
Hyperpolarized gas MRI is a technique that uses the alignment of nuclear spins in certain gases, such as 3He or 129Xe, to create detailed images of the body's internal structures. In order for the nuclear spins to be used for imaging, they must be aligned in the same direction, or polarized. Under normal conditions, the nuclear spins within the gas volume are randomly aligned, leading to a zero signal.
Once the nuclear spins have been polarized, they can be placed in a large magnetic field, such as that of a 1.5T or 3.0T scanner. This will cause slightly more spins to align with the field than against it. However, this difference is not sufficient for imaging dilute gases like 3He or 129Xe. Therefore, hyperpolarization techniques are used to add angular momentum to the system and align all of the nuclear spins in the same direction, resulting in a strong signal that can be used to create detailed images of the body's tissues.
Optical pumping
Hyperpolarization is the process of aligning the nuclear spins in a gas, such as 3He or 129Xe, in the same direction to create a strong signal for imaging. To accomplish this, angular momentum is added to the system through the use of circularly polarized laser light. Since nuclei cannot directly absorb laser light, an intermediary is used to absorb the light and transfer its angular momentum to the nuclei.
This intermediary is typically an alkali metal atom, such as rubidium, whose outer-shell valence electron is aligned by the laser light. Only atoms with electron spins that are down can absorb the light, so illuminating the alkali vapor with circularly polarized resonant light will convert the entire sample to the spin up direction. Once a valence electron spin has been flipped up, it remains aligned until collisions cause it to depolarize. However, it can simply absorb another photon and return to the aligned state. This process, known as optical pumping, allows for the efficient alignment of nuclear spins in the gas.
Spin exchange
The alignment of the valence electron is then transferred to the noble-gas nuclei through collisions with polarized electron spins of the rubidium. This process is called spin exchange. The rubidium electrons are then aligned again by absorbing additional laser light and continue to build polarization in the noble-gas nuclei. Current techniques using optical pumping and spin exchange can achieve polarizations of around 40-80% for 3He and 10-40% for 129Xe. Recently, very high peak polarization levels for 129Xe have been demonstrated in diluted mixtures.
Mechanism of hyperpolarization
The process of optical pumping uses rubidium (Rb) contained in a glass optical cell. This cell is placed in an oven with two Helmholtz coils that generate a small, but homogenous 20 G magnetic field. The Rb is heated to around 150 °C to produce a vapor pressure of about 1ppm of the total gas density in the cell. Circularly polarized laser light is then directed at the cell, which is tuned to the D1 transition of rubidium. This light is absorbed by the Rb vapor, polarizing the valence electron spins on the Rb atoms.
Spin exchange is a process that begins when a mixture of 1% 129Xe, 89% 4He and 10% N2 is directed to flow through an optical cell that contains optically pumped Rubidium (Rb) atoms. The buffer gases, helium and nitrogen, serve to broaden the Rb absorption cross section, allowing a large fraction of laser light to be absorbed and used to polarize the valence electron spins of the Rb atoms. Through a combination of binary collisions and the formation of transient Van der Waals complexes, the electron spin polarization is transferred to the 129Xe nuclei. The gas flow rate is regulated to ensure that the 129Xe emerges from the cell with a high level of polarization. To separate the 129Xe from the helium and nitrogen, it is cryogenically accumulated in a cold finger immersed in liquid nitrogen. Since xenon has a higher freezing point than the other gases, it is frozen out and separated from them. Once a sufficient amount of xenon has been accumulated, it is thawed and dispensed into a perfluoropolymer bag. The xenon polarization is then measured using a low-field NMR-based system and delivered to the patient for use in MRI imaging. Commercially available systems can produce liters of xenon polarized to 10-15% within an hour. Advances in polarization physics are expected to improve both the production rate and polarization of 129Xe in the future.
In order to obtain images of the subject's lung tissue, the polarized xenon gas is inhaled through a tube connected to a mouthpiece. The subject is instructed to take a deep breath and exhale fully twice before inhaling the gas. The typical scan uses a mixture of 200-1000 ml of 129Xe and a buffer gas such as helium or nitrogen. This mixture is inhaled by the subject and used to create detailed images of the lung tissue.
Applications
Ventilation imaging
HP 3He gas MR imaging of the lungs has been confirmed to be effective in multiple clinical studies since 1997. This technique is mainly used to create images of gas distribution in the lungs, allowing for the identification of ventilation defects. These defects can be caused by blocked airways or destruction of lung tissue. The MR signal intensities in the ventilation images can be grouped into four clusters for analysis. Low or absent signal within the lungs corresponds well with ventilation defects and allows for the detection and quantification of functional ventilation impairment in conditions such as asthma, COPD, and cystic fibrosis. Data acquisition for this technique is completed in a single breath-hold, providing static ventilation information. Dynamic ventilation properties, such as gas flow, are more difficult to measure but progress has been made in this area.
Traditionally, HP 3He provided better image quality due to its larger polarization compared to 129Xe. However, recent improvements in polarization technology and MR acquisition have allowed 129Xe to produce images of similar quality to 3He. In terms of detecting ventilation defects, 129Xe has a lower signal-to-noise ratio but is more sensitive to defects due to its higher density and lower diffusivity. Currently, using a larger volume of 129Xe (up to 1 liter per scan) can compensate for its decreased signal-to-noise ratio compared to 3He (usually 0.1-0.3 liters per scan).
Diffusion weighted imaging
Diffusion-weighted MRI has been proven effective and is commonly used with hyperpolarized gases to calculate the apparent diffusion coefficient (ADC) of the gas. This is done by taking gas images with and without diffusion sensitizing gradients. The usefulness of this contrast comes from the fact that the diffusion of gases is limited by the structure of healthy lungs. In diseases like emphysema, where the airspaces are larger, the gases are free to diffuse more easily. This allows diffusion-weighting to differentiate normal airspaces from enlarged ones based on the degree of signal attenuation. The signal intensities in the weighted and non-weighted images are then used to calculate the ADC on a voxel-by-voxel basis. ADC maps show low values in healthy lung tissue, but in emphysematous lungs, elevated ADC values are often seen. In addition to showing emphysema, 3He or 129Xe ADC values have been found to be sensitive to early changes in the lung tissue of smokers and people exposed to second-hand smoke. ADC MRI has also been shown to be sensitive to age-related changes in alveolar size in healthy individuals. Comparisons to CT densitometry have shown that ADC strongly correlates with DLCO and may be able to detect early emphysema before it is visible on CT scans. While most ADC imaging has used 3He MRI, it has recently been shown that 129Xe can also be used for this purpose.
Future direction
129Xe dissolving imaging
Xenon has a lower gyromagnetic ratio and lower SNR in images than helium. However, it has the useful property of being moderately soluble in lung tissue. This allows it to diffuse into the capillaries and blood stream, where it experiences shifts in frequency that provide information about gas exchange in the lungs. These shifts can be used to study ventilatory distribution and diffusive gas exchange.
Imaging the dissolved-phase of gases in the lungs can be difficult. The signal intensity in this phase is only 2% of the gas-phase, and its T2* is very fast at 2 ms. Additionally, the dissolved-phase resonances are 200 ppm from the gas-phase on a 1.5T scanner, so RF excitation pulses must be carefully tuned to avoid exciting the gas-phase.
Early attempts at imaging the dissolved-phase used indirect methods like Xenon Polarization Transfer Contrast (XTC). This method used RF pulses applied to the dissolved-phase to slightly attenuate the gas-phase signal, allowing for the indirect mapping of the dissolved-phase distribution. As polarization and pulse sequence technology improved, direct imaging of dissolved 129Xe became possible. By using frequency-selective RF pulses and a 3D radial pulse sequence, the first direct images of the dissolved-phase in humans were acquired in 2010. These images were lower resolution due to the small signal intensity of dissolved-phase 129Xe, but still showed interesting aspects of lung function. Soon after this technique was introduced, Mugler et al. showed the value of acquiring the gas-phase distribution in the same breath, allowing for the quantification of the dissolved-phase distribution. This was later extended to a radial acquisition strategy, which allowed for the analysis of the effects of posture on gas transfer.
It is important to be able to separately detect the transfer of 129Xe to red blood cells (RBCs) because the pathway xenon follows to reach RBCs is the same as that of oxygen. Recently, spectra of 129Xe in the dissolved phase were acquired in subjects with idiopathic pulmonary fibrosis and showed greatly reduced 129Xe transfer to RBCs compared to healthy volunteers. This work showed that separating the dissolved 129Xe resonances is critical for detecting diffusion limitation caused by lung tissue thickening. 129Xe measurements correlated strongly with DLCO and showed that the frequency of the 129Xe RBC resonance may be a sensitive measure of blood oxygenation at the capillary level. This work also emphasized the need for imaging to separately detect xenon uptake in barrier tissues and RBCs.
Separately imaging 129Xe in barrier tissues and RBCs is similar to separating fat and water in 1H MRI. The two resonances are similarly spaced, so fat-water separation algorithms can be used. Qing et al. used the Hierarchical IDEAL algorithm to image all three resonances of xenon in a single breath. The 1-point Dixon strategy has also been successful and may be more robust against the short T2* of the dissolved-phase 129Xe signal. This technique was also recently used to image all three resonances of xenon in a single breath.
See also
Xenon gas MRI
References
Magnetic resonance imaging | Hyperpolarized gas MRI | [
"Chemistry"
] | 3,730 | [
"Nuclear magnetic resonance",
"Magnetic resonance imaging"
] |
72,411,605 | https://en.wikipedia.org/wiki/Silvilization | Silvilization is a conceptual framework or a vision of the world whereby the forest, a metaphor for primordial living, is the best place for human development and fulfilment. It is a portmanteau of the Latin word silva, meaning forest, and civilization.
History
The term was first coined by Pierre-Doris Maltais, leader of the Iriadamant eco-cult. Erkki Pulliainen, an MP of the Green League, in collaboration with Maltais and the University of Helsinki, implemented the interdisciplinary ESSOC project (“Ecological Sylvilisation and Survival with the Aid of Original Cultures”) in 1991. The project was considered a failure.
In 1997, a publication in the journal Interculture by the Intercultural Institute of Montreal was devoted entirely to the theme of silvilization and ecosophy. The articles were written by authors such as Edward Goldsmith, Gary Snyder, and Gita Mehta.
References
Sociology
Ecology | Silvilization | [
"Biology"
] | 198 | [
"Behavioural sciences",
"Behavior",
"Ecology",
"Sociology"
] |
72,412,136 | https://en.wikipedia.org/wiki/Operation%20Cyberstorm | Operation Cyberstorm was a two-year undercover operation in the United States by the Federal Bureau of Investigation (FBI), against illegal copying of software. At the time, it was the largest sweep ever conducted by the FBI against illegal copying.
Investigations
A number of individuals purchased software at discounts, and resold them at a profit in violation of their software license.
Convictions
Mirza Ali, 60, of Fremont, California and Sameena Ali, 53, also of Fremont, were sentenced in 2007 to 60 months imprisonment, and forfeiture in the amount of $5,105,977. Keith Griffen, 56, of Oregon City, Oregon, was sentenced to 33 months of imprisonment, restitution to Microsoft Corporation in the amount of $20,000,000, three years of supervised release, and $900 in special assessments. William Glushenko, 66, was sentenced to one year of probation and 100 hours of community service after pleading guilty to misprision of felony.
References
Cyberstorm
Copyright enforcement
Cyberstorm | Operation Cyberstorm | [
"Technology"
] | 209 | [
"Computer security stubs",
"Computing stubs"
] |
63,697,055 | https://en.wikipedia.org/wiki/Surface%20differential%20reflectivity | Surface differential reflectivity (SDR) or differential reflectance spectroscopy (DRS) is a spectroscopic technique that measures and compares the reflectivity of a sample in two different physical conditions (modulation spectroscopy). The result is presented in terms of ΔR/R, which is defined as follow:
where R1 and R2 represent the reflectivity due to a particular state or condition of the sample.
The differential reflectivity is used to enhance just the contributions to the reflected signal coming from the sample. In fact, the light penetration (α−1) inside a solid is related to the adsorption coefficient (α) of the material. The contribution of the sample surface (e.g., surface states, ultra-thin and thin deposited films, etc.) to the reflected signal is generally evaluated in the 10−2 range. The difference between two sample states (1 and 2) is thought to put in evidence small changes occurring onto the sample surface. If R1 represents a clean freshly prepared surface (e.g., after a cleavage in vacuum) and R2 the same sample after the exposure to hydrogen or oxygen contaminants, the ΔR/R spectrum can be related to features of the clean surface (e.g., surface states); if R1 is the reflectivity spectrum of a sample covered by an organic film (even if the substrate is only partially covered) and R2 represents the optical spectrum of the pristine substrate, the ΔR/R spectrum can be related to the optical properties of the deposited molecules; etc.
The experimental SDR definition reported was interpreted in terms of surface (or film) thickness (d) and its dielectric function (ε2 = ε’2 - iε”2). This model, which assumes the surface as a well-defined phase above a bulk, is known as the “three-layer model” and states that:
where ε1 = 1 is the vacuum dielectric constant and ε3 = ε’3 - iε”3 is the bulk dielectric function.
The SDR measurements are generally realized by exploiting an optical multichannel system coupled with a double optical path in the so-called Michelson-cross configuration.
In this configuration, the ΔR/R signal is obtained by a direct comparison between the reflectivity signal R1 arises from the sample (e.g., a silicon substrate covered by a few amount of molecules) placed inside the UHV chamber (first optical path) and the R2 signal acquired from a reference sample (dummy sample; e.g., a silicon wafer) placed along the second optical path. The difference between R1 and R2 is due to the deposited molecules, which can affect the reflectivity signal in the 10−3÷10−2 range of the overall reflected signal of the real sample. Consequently, a high signal stability is required and the two optical paths must be as comparable as possible.
The SDR apparatus was firstly described and used by G. Chiarotti for the investigation of the surface states contribution in the Ge(111) reflectivity properties. This work also represents the first direct evidence of the existence of surface states in semiconductors. An evolution of the SDR set-up by using linearly polarized light was firstly described by P. Chiaradia and co-workers for testing the structure of the Si(111) 2 × 1 surface. Other equivalent SDR set-up have been exploited for studying: the surface roughening evolution, the reactivity of halogens with semiconductor surfaces, the adhesion of nanoparticles during their growth, the growth of heavy metals on semiconductors, the nano-antennas characterization, just to mention some of the works related to this surface optical technique.
References
Spectroscopy | Surface differential reflectivity | [
"Physics",
"Chemistry"
] | 769 | [
"Instrumental analysis",
"Molecular physics",
"Spectroscopy",
"Spectrum (physical sciences)"
] |
63,698,532 | https://en.wikipedia.org/wiki/Bulky%20cyclopentadienyl%20ligands | In the area of organometallic chemistry, a bulky cyclopentadienyl ligand is jargon for a ligand of the type where R is a branched alkyl and n = 3 or 4. Representative examples are the tetraisopropyl derivative and the tris(tert-butyl) derivative . These ligands are so large that their complexes behave differently from the pentamethylcyclopentadienyl analogues. Because they cannot closely approach the metal, these bulky ligands stabilize high spin complexes, such as (C5H2tBu3)2Fe2I2. These large ligands stabilize highly unsaturated derivatives such as (C5H2tBu3)2Fe2N2.
Synthesis and reactions
The (tert-butyl)cyclopentadiene is prepared by alkylation of cyclopentadiene with tert-butyl bromide in the presence of sodium hydride and dibenzo-18-crown-6. The intermediate in this synthesis is di-tert-butylcyclopentadiene. This compound is conveniently prepared by alkylation of cyclobutadiene with tert-butyl bromide under phase-transfer conditions.
Illustrative of the unusual complexes made possible with these bulky ligands is molecular iron nitrido complex (tBu3C5H2)2Fe2N2. In contrast to (C5Me5)2Ir2Cl4, (tBu3C5H2)IrCl2 is monomeric.
References
Organometallic chemistry | Bulky cyclopentadienyl ligands | [
"Chemistry"
] | 338 | [
"Organometallic chemistry",
"Cyclopentadienyl complexes"
] |
63,699,828 | https://en.wikipedia.org/wiki/Cable-suspended%20camera%20system | A cable-suspended camera system is a system of cables above or along an area to be filmed or videoed, over or along which an attached camera head travels to achieve required camera angles.
There are two broad types cable-suspended camera systems: fixed-cable and moving-cable types.
Fixed-cable type
In fixed-cable type cable-suspended camera systems, the cable is attached at fixed anchor points and a motorized camera head travels along the fixed cable. This kind of system can be advantageous over longer distances and where it might be difficult to set up winches with moving cables, or in no fly zones. Some use cases have a camera head running along the ground in trolley mode for a kind of tracking shot.
In recent years, fixed-cable suspended camera systems has become popular for professional live TV broadcast and film production to shoot sport and entertainment events. A widely used system is the Defy Dactylcam, which travels along the cable with a motor, and the Newton stabilized camera head which controls the camera and lens. This system is for example used at the live TV broadcast of Major League Baseball, UEFA (football), track and field, concerts and ski competitions.
There has also been an upsurge of low budget amateur cablecam systems for action cameras and even cellphones that is used for: amateur sports videos, hobby video, lower budget film and video, photography, and motion time-lapse footage.
Companies selling fixed-cable suspended camera systems include: Newton Nordic, Flyline, Defy Products, High Sight, Wiral and Syrp.
Moving-cable type
In moving-cable type cable-suspended camera systems, cables are attached to winches at their ends to allow movement of an attached camera head between multiple cables. There are several variants of moving-cable type cable-suspended camera systems, including:
3D moving-cable type cable-suspended camera systems, a.k.a. suspended flying camera systems, with four cables moving an attached camera head in three dimensions;
2D moving-cable type cable-suspended camera systems, with two cables moving an attached camera head vertically and horizontally;
Point-to-point (1D) moving-cable type cable-suspended camera systems where there is one cable pulling an attached camera head between two fixed points.
3D moving-cable
3D moving-cable type cable-suspended camera systems, a.k.a. suspended flying camera systems, are used by broadcasters and video production companies to create dynamic video footage of sporting events and cultural events like concerts. They are a type of cable robot.
Advantages include reducing or eliminating the need for crane shots, using camera cranes or jibs that might obstruct spectator sight lines or take up valuable space or interfere with a shot.
Commercial 3D moving-cable type cable-suspended camera systems include: EagleEye, Spydercam, SkyCam, Spidercam, and RobyCam 3D.
Events that have been photographed using 3D moving-cable type cable-suspended camera systems include: NFL games (e.g., when the Skycam captured the Chicago Bears' Cordarrelle Patterson's 102-yard kickoff return touchdown on October 20, 2019), WWE matches, Tennis, Cricket, Rugby, Soccer, concerts (Spidercam), swimming and esports (RobyCam).
2D moving-cable
2D moving-cable type cable-suspended camera systems typically move in the horizontal (X) and vertical (Z) planes are used by broadcasters and video production companies to create dynamic video footage where other types of systems are impractical or impossible to set up because of venue/location.
Commercial 2D moving-cable type cable-suspended camera systems include the RobyCam 2D and CamCat's CamCat 2D. and the RTS RopeClimber that has for example been used at the Oscars 2019 and 2020
Point-to-point (1D) moving-cable
Point-to-point moving-cable type cable-suspended camera systems are used to draw a camera head or dolly between two fixed points. These systems tend to move faster than 3D and 2D systems and are thus used for sports where speed is a factor like horse-racing, skiing and extreme sports.
Commercial point-to-point (1D) moving-cable type cable-suspended camera systems include Robyline (used at Biathlon World Cup, FIS Alpine Ski World Cup and Supercoppa Italiana)
References
Cameras | Cable-suspended camera system | [
"Technology"
] | 893 | [
"Recording devices",
"Cameras"
] |
63,699,872 | https://en.wikipedia.org/wiki/Sentinel%20surveillance | Sentinel surveillance is monitoring of rate of occurrence of specific diseases and conditions through a voluntary network of doctors, laboratories and public health departments with a view to assess the stability or change in health levels of a population. It also describes the study of disease rates in a specific cohort such as a geographic area or subgroup to estimate trends in a larger population. In zoonotic diseases, sentinel surveillance may be in a host species.
Purpose
A sentinel surveillance system is used to obtain data about a particular disease that cannot be obtained through a passive system such as summarizing standard public health reports. Data collected in a well-designed sentinel system can be used to signal trends, identify outbreaks and monitor disease burden, providing a rapid, economical alternative to other surveillance methods.
Method
Sentinel systems involve a network of reporting sites, typically doctors, laboratories and public health departments. Surveillance sites must offer:
commitment to resource the program
a high probability of observing the target disease,
a laboratory capable of systematically testing subjects for the disease,
experienced, qualified staff.
relatively large population with easy site access
Passive surveillance
Passive surveillance systems receive data from "all" (or as many as possible) health workers/facilities and is the most common method of tracking communicable diseases. Passive surveillance does not require health authorities to stimulate reporting by reminding health care workers. Workers may receive the surveillance training in how to complete surveillance forms. Passive surveillance is often incomplete because of the limited reporting incentives.
Systems
Sentinel systems collect data on Haemophilus influenzae type b, meningococcus and pneumococcus.
Because sentinel surveillance is conducted only at selected locations, it is not as appropriate for use on rare diseases or outbreaks distant from sentinel sites.
COVID-19
The state of Hawaii conducts a sentinel surveillance program for COVID-19. From March 1-April 11, 2020, Hawaii's system detected 23 cases of COVID-19 among 1,084 specimens tested (2.1%). Samples were selected to match the state's geographic and age distribution. In Santa Clara, California, researchers analyzed sentinel surveillance data from March 5–14, 2020. From this sample, 19 out of 226 participants (8%) had COVID-19.
See also
Epidemiology
References
External links
Infectious diseases
Medical statistics
Epidemiology | Sentinel surveillance | [
"Environmental_science"
] | 469 | [
"Epidemiology",
"Environmental social science"
] |
63,699,886 | https://en.wikipedia.org/wiki/Knee%20of%20a%20curve | In mathematics, a knee of a curve (or elbow of a curve) is a point where the curve visibly bends, specifically from high slope to low slope (flat or close to flat), or in the other direction. This is particularly used in optimization, where a knee point is the optimum point for some decision, for example when there is an increasing function and a trade-off between the benefit (vertical y axis) and the cost (horizontal x axis): the knee is where the benefit is no longer increasing rapidly, and is no longer worth the cost of further increases – a cutoff point of diminishing returns.
In heuristic use, the term may be used informally, and a knee point identified visually, but in more formal use an explicit objective function is used, and depends on the particular optimization problem. A knee may also be defined purely geometrically, in terms of the curvature or the second derivative.
Definitions
The knee of a curve can be defined as a vertex of the graph. This corresponds with the graphical intuition (it is where the curvature has a maximum), but depends on the choice of scale.
The term "knee" as applied to curves dates at least to the 1910s,
and is found more commonly by the 1940s, being common enough to draw criticism. The unabridged Webster's Dictionary (1971 edition) gives definition 3h of knee as:
Criticism
Graphical notions of a "knee" of a curve, based on curvature, are criticized due to their dependence on the coordinate scale: different choices of scale result in different points being the "knee". This criticism dates at least to the 1940s, being found in , who criticize:
Detection methods
The Kneedle algorithm The algorithm detects the best balanced tradeoff based on the mathematical curvature concept, which is defined and well studied for continuous functions. Alternatively, the kneepointDetection() function from the SamSPECTRAL R package can be used to find the knee point, where is a "phase change" in the data, by fitting two lines using linear regression.
Applications
Elbow method
Maximum power point tracking
References
Curvature (mathematics)
Mathematical optimization
Operations research | Knee of a curve | [
"Physics",
"Mathematics"
] | 436 | [
"Geometric measurement",
"Mathematical analysis",
"Physical quantities",
"Applied mathematics",
"Operations research",
"Mathematical optimization",
"Curvature (mathematics)"
] |
63,700,412 | https://en.wikipedia.org/wiki/The%20Banach%E2%80%93Tarski%20Paradox%20%28book%29 | The Banach–Tarski Paradox is a book in mathematics on the Banach–Tarski paradox, the fact that a unit ball can be partitioned into a finite number of subsets and reassembled to form two unit balls. It was written by Stan Wagon and published in 1985 by the Cambridge University Press as volume 24 of their Encyclopedia of Mathematics and its Applications book series. A second printing in 1986 added two pages as an addendum, and a 1993 paperback printing added a new preface.
In 2016 the Cambridge University Press published a second edition, adding Grzegorz Tomkowicz as a co-author, as volume 163 of the same series. The Basic Library List Committee of the Mathematical Association of America has recommended its inclusion in undergraduate mathematics libraries.
Topics
The Banach–Tarski paradox, proved by Stefan Banach and Alfred Tarski in 1924, states that it is possible to partition a three-dimensional unit ball into finitely many pieces and reassemble them into two unit balls, a single ball of larger or smaller area, or any other bounded set with a non-empty interior. Although it is a mathematical theorem, it is called a paradox because it is so counter-intuitive; in the preface to the book, Jan Mycielski calls it the most surprising result in mathematics. It is closely related to measure theory and the non-existence of a measure on all subsets of three-dimensional space, invariant under all congruences of space, and to the theory of paradoxical sets in free groups and the representation of these groups by three-dimensional rotations, used in the proof of the paradox. The topic of the book is the Banach–Tarski paradox, its proof, and the many related results that have since become known.
The book is divided into two parts, the first on the existence of paradoxical decompositions and the second on conditions that prevent their existence. After two chapters of background material, the first part proves the Banach–Tarski paradox itself, considers higher-dimensional spaces and non-Euclidean geometry, studies the number of pieces necessary for a paradoxical decomposition, and finds analogous results to the Banach–Tarski paradox for one- and two-dimensional sets. The second part includes a related theorem of Tarski that congruence-invariant finitely-additive measures prevent the existence of paradoxical decompositions, a theorem that Lebesgue measure is the only such measure on the Lebesgue measurable sets, material on amenable groups, connections to the axiom of choice and the Hahn–Banach theorem. Three appendices describe Euclidean groups, Jordan measure, and a collection of open problems.
The second edition adds material on several recent results in this area, in many cases inspired by the first edition of the book. Trevor Wilson proved the existence of a continuous motion from the one-ball assembly to the two-ball assembly, keeping the sets of the partition disjoint at all times; this question had been posed by de Groot in the first edition of the book. Miklós Laczkovich solved Tarski's circle-squaring problem, asking for a dissection of a disk to a square of the same area, in 1990. And Edward Marczewski had asked in 1930 whether the Banach–Tarski paradox could be achieved using only Baire sets; a positive answer was found in 1994 by Randall Dougherty and Matthew Foreman.
Audience and reception
The book is written at a level accessible to mathematics graduate students, but provides a survey of research in this area that should also be useful to more advanced researchers. The beginning parts of the book, including its proof of the Banach–Tarski paradox, should also be readable by undergraduate mathematicians.
Reviewer Włodzimierz Bzyl writes that "this beautiful book is written with care and is certainly worth reading". Reviewer John J. Watkins writes that the first edition of the book "became the classic text on paradoxical mathematics" and that the second edition "exceeds any possible expectation I might have had for expanding a book I already deeply treasured".
See also
List of paradoxes
History of mathematics
References
Geometric dissection
Mathematical paradoxes
Mathematics books
1985 non-fiction books
2016 non-fiction books
Cambridge University Press books | The Banach–Tarski Paradox (book) | [
"Mathematics"
] | 873 | [
"Mathematical problems",
"Mathematical paradoxes"
] |
63,701,697 | https://en.wikipedia.org/wiki/Trimethylsilyl%20isothiocyanate | Trimethylsilyl isothiocyanate (TMSNCS) is an organosilicon compound that contains an isothiocyanate whose nitrogen atom is covalently bonded to a trimethylsilyl group. The isothiocyanate group is an analog of the isocyanate group, but having a sulfur instead of oxygen.
Reactions
TMSNCS is useful reagent in organic chemistry. It is an ambident nucleophile, able to react with various alkyl halides, acetals, aldehydes, unsaturated compounds, aziridines, oxiranes, polycyclic aromatic hydrocarbons, and acetylated hexoses to form either thiocyanate or isothiocyanate structures. As an electrophile, it can react with other nucleophiles to form thioamide types of structures, some of which can undergo subsequent reactions to form heterocycles.
Halide substitutions
As a sulfur nucleophile, TMSNCS substitutes for halides on a range of alkyl substrates, giving alkyl thiocyanates. These substitution reactions involve tetrabutylammonium fluoride used as phase-transfer catalyst and occur under particularly mild conditions.
Reactions with aldehydes and acetals
As a nitrogen nucleophile, TMSNCS adds across the carbonyl group of aldehydes and substitutes isothiocyanate for one of the ether groups on acetals via acid-catalyzed processes.
Mercapto-1,2,4-triazoles
A one-step method to prepare mercapto-1,2,4-tiazoles is favored on the industrial scale due to its high efficiency (88% yield) and non-constraining conditions: not requiring anhydrous solvent, inert gas temperature, or chromatographic purification. The method can be summarized as follows: after the equimolar mixture of benzohydrazide and TMSNCS reflux in the presence of EtOH for 5 hours, NaOH is added to the reaction mixture and the solution is refluxed for 4 h. Acetic acid is then used to cool and neutralize, ultimately yielding the pure white solid 3-phenyl-5-mercapto-4H-1,2,4-triazole at 88% yield.
2-Amino-1,3,4-oxadiazoles
TMSNCS used for the synthesis of 2-amino-1,3,4-oxadiazoles. The TMSNCS reagent assists in the production of the thiosemicarbazide and the subsequent reaction (cyclodesulfurization of thiosemicarbazides under basic conditions in the presence of I2/KI) results in 2-amino-1,3,4-oxadiazoles in high yields (79–94%).
The 2-amino-1,3,4-oxadiazoles resulting from this reaction are: 2-Amino-5-phenyl-1,3,4-oxadiazole, 2-Amino-5-(p-methylphenyl)-1,3,4-oxadiazole, 2-Amino-5-(p-chlorophenyl)-1,3,4-oxadiazole, 2-Amino-5-(p-methoxyphenyl)- 1,3,4-oxadiazole, 2-Amino-5-(p-nitrophenyl) -1,3,4-oxadiazole, 2-Amino-5-(o-methylphenyl)-1,3,4-oxadiazole, 2-Amino-5-(o-chlorophenyl)-1,3,4-oxadiazole, ect.
Notes
Isothiocyanates
Trimethylsilyl compounds | Trimethylsilyl isothiocyanate | [
"Chemistry"
] | 848 | [
"Isothiocyanates",
"Functional groups",
"Trimethylsilyl compounds"
] |
63,701,801 | https://en.wikipedia.org/wiki/Centre%20International%20de%20Recherche%20en%20Infectiologie | The Centre International de Recherche en Infectiologie is an academic and research institute based in Lyon, France.
Synopsis
The CIRI is composed of 22 teams gathered behind one goal: the fight against infectious diseases (which is the second cause of death worldwide) by "promoting in-depth conceptual and technological advances through approaches that span from fundamental to clinical/applied research." The key areas of expertise of the CIRI teams are bacteriology, immunology and virology.
The CIRI contains a Biosafety Level 4 laboratory.
History
The CIRI was created in 2013 by the Inserm, the CNRS, the ENS de Lyon and the Université Claude Bernard Lyon 1 in partnership with the Pasteur Institute, the Mérieux Foundation, the VetAgroSup and the Hospices Civils de Lyon.
A BSL-4 laboratory at the Wuhan Institute of Virology received significant and substantial support of the conceptual, engineering and logistical varieties from the CIRI. The WIV BSL-4 facility was commissioned in February 2015.
References
Laboratories in France
Virology institutes
Research institutes in France
Inserm
Medical research institutes in France
Biosafety level 4 laboratories
Life sciences industry
2013 establishments in France
Organizations based in Lyon | Centre International de Recherche en Infectiologie | [
"Biology"
] | 259 | [
"Life sciences industry"
] |
63,703,274 | https://en.wikipedia.org/wiki/DF-space | In the mathematical field of functional analysis, DF-spaces, also written (DF)-spaces are locally convex topological vector space having a property that is shared by locally convex metrizable topological vector spaces. They play a considerable part in the theory of topological tensor products.
DF-spaces were first defined by Alexander Grothendieck and studied in detail by him in .
Grothendieck was led to introduce these spaces by the following property of strong duals of metrizable spaces: If is a metrizable locally convex space and is a sequence of convex 0-neighborhoods in such that absorbs every strongly bounded set, then is a 0-neighborhood in (where is the continuous dual space of endowed with the strong dual topology).
Definition
A locally convex topological vector space (TVS) is a DF-space, also written (DF)-space, if
is a countably quasi-barrelled space (i.e. every strongly bounded countable union of equicontinuous subsets of is equicontinuous), and
possesses a fundamental sequence of bounded (i.e. there exists a countable sequence of bounded subsets such that every bounded subset of is contained in some ).
Properties
Let be a DF-space and let be a convex balanced subset of Then is a neighborhood of the origin if and only if for every convex, balanced, bounded subset is a neighborhood of the origin in Consequently, a linear map from a DF-space into a locally convex space is continuous if its restriction to each bounded subset of the domain is continuous.
The strong dual space of a DF-space is a Fréchet space.
Every infinite-dimensional Montel DF-space is a sequential space but a Fréchet–Urysohn space.
Suppose is either a DF-space or an LM-space. If is a sequential space then it is either metrizable or else a Montel space DF-space.
Every quasi-complete DF-space is complete.
If is a complete nuclear DF-space then is a Montel space.
Sufficient conditions
The strong dual space of a Fréchet space is a DF-space.
The strong dual of a metrizable locally convex space is a DF-space but the convers is in general not true (the converse being the statement that every DF-space is the strong dual of some metrizable locally convex space). From this it follows:
Every normed space is a DF-space.
Every Banach space is a DF-space.
Every infrabarreled space possessing a fundamental sequence of bounded sets is a DF-space.
Every Hausdorff quotient of a DF-space is a DF-space.
The completion of a DF-space is a DF-space.
The locally convex sum of a sequence of DF-spaces is a DF-space.
An inductive limit of a sequence of DF-spaces is a DF-space.
<li>Suppose that and are DF-spaces. Then the projective tensor product, as well as its completion, of these spaces is a DF-space.<li>
However,
An infinite product of non-trivial DF-spaces (i.e. all factors have non-0 dimension) is a DF-space.
A closed vector subspace of a DF-space is not necessarily a DF-space.
There exist complete DF-spaces that are not TVS-isomorphic to the strong dual of a metrizable locally convex TVS.
Examples
There exist complete DF-spaces that are not TVS-isomorphic with the strong dual of a metrizable locally convex space.
There exist DF-spaces having closed vector subspaces that are not DF-spaces.
See also
Citations
Bibliography
External links
DF-space at ncatlab
Topology
Topological vector spaces
Functional analysis | DF-space | [
"Physics",
"Mathematics"
] | 817 | [
"Functions and mappings",
"Functional analysis",
"Vector spaces",
"Mathematical objects",
"Space (mathematics)",
"Topological vector spaces",
"Topology",
"Space",
"Mathematical relations",
"Geometry",
"Spacetime"
] |
63,703,323 | https://en.wikipedia.org/wiki/Di-tert-butylcyclopentadiene | Di-tert-butylcyclopentadiene is an organic compound with the formula (Me3C)2C5H4, where Me = methyl. It is a colorless liquid that is soluble in organic solvents. The compound is the conjugate acid of the di-tert-butylcyclopentadienyl ligand, (Me3C)2C5H3− (sometimes abbreviated Cp‡−). Two regioisomers of di-tert-butylcyclopentadiene exist, depending on the relative location of the double bonds.
Synthesis and reactions
Di-tert-butylcyclopentadiene is prepared by alkylation of cyclopentadiene with tert-butyl bromide under phase-transfer conditions.
It is the precursor to many metal complexes, such as the olefin polymerization catalyst ((Me3C)2C5H3)TiCl3.
The conjugate base of di-tert-butylcyclopentadiene reacts with a third equivalent of tert-butyl bromide to give (Me3C)3C5H3:
(Me3C)2C5H4 + NaH → Na(Me3C)3C5H3 + H2
Na(Me3C)2C5H3 + Me3CBr → (Me3C)3C5H3 + NaBr
References
Cyclopentadienes
Ligands | Di-tert-butylcyclopentadiene | [
"Chemistry"
] | 314 | [
"Ligands",
"Coordination chemistry"
] |
63,703,703 | https://en.wikipedia.org/wiki/Statistical%20Physics%20of%20Particles | Statistical Physics of Particles and Statistical Physics of Fields are a two-volume series of textbooks by Mehran Kardar. Each book is based on a semester-long course taught by Kardar at the Massachusetts Institute of Technology. They cover statistical physics and thermodynamics at the graduate level.
Editions
External links
Statistical Mechanics I at MIT OpenCourseWare
Statistical Mechanics II at MIT OpenCourseWare
Publisher's website for Particles
Publisher's website for Fields
References
2007 non-fiction books
Physics textbooks
Statistical mechanics | Statistical Physics of Particles | [
"Physics"
] | 107 | [
"Statistical mechanics stubs",
"Statistical mechanics"
] |
63,704,851 | https://en.wikipedia.org/wiki/Charles%20Babbage%20Premium | The Charles Babbage Premium was an annual award "for an outstanding paper on the design or use of electronic computers".
The award was established in 1959. It was initiated by the British Institution of Radio Engineers, which became the Institution of Electronic and Radio Engineers. In 1988, it merged with the Institution of Electrical Engineers (IEE), which later became the Institution of Engineering and Technology (IET) in 2006. Winners have been announced in journals such as Nuclear Power, Electronic Engineering, British Communications and Electronics, and the Software Engineering Journal.
The Premium was named after the mathematician Charles Babbage FRS (1791–1871), inventor of the Analytical Engine, a design for an early mechanical computer.
The IET now makes separate Premium Awards for papers in each of its journals, named after the journal itself. This includes the IET Software Premium Award, the nearest equivalent to the Charles Babbage Premium Award.
References
1959 establishments in the United Kingdom
1988 disestablishments in the United Kingdom
Awards established in 1959
Awards disestablished in 1988
Awards for scholarly publications
British awards
Computer science awards
Institution of Engineering and Technology
Premium | Charles Babbage Premium | [
"Technology",
"Engineering"
] | 230 | [
"Computer science awards",
"Institution of Engineering and Technology",
"Science award stubs",
"Computer science",
"Science and technology awards"
] |
63,705,763 | https://en.wikipedia.org/wiki/Dendroaspis%20natriuretic%20peptide | Dendroaspis natriuretic peptide (DNP) is a 38-residue peptide and a member of natriuretic peptide family. It is structurally similar to the atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP) and possesses biologic properties similar to these natriuretic peptides.
DNP was originally isolated from the venom of the green mamba snake (Dendroaspis angusticeps), from which its name is derived.
References
Peptides
Snakes | Dendroaspis natriuretic peptide | [
"Chemistry"
] | 125 | [
"Biomolecules by chemical classification",
"Peptides",
"Molecular biology"
] |
63,707,346 | https://en.wikipedia.org/wiki/Kharaneh%20IV | Kharaneh IV (referred to as Kharaneh 4 in some sources) is an archaeological site in Jordan. The site contains evidence of human activity dating to the Late Pleistocene. Its main period of occupation was 18,900 to 16,600 BC.
Description
Kharaneh IV is located in the Wadi Kharaneh near the town of Azraq, Jordan. It was first recorded by F. E. Zeuner in 1955. Excavations at the site began under M. Muheisen in the 1980s and were resumed in 2008 under the direction of Lisa Maher and Danielle Macdonald. In the 2010 field season, Maher's and Macdonald's team discovered two hut structures thought to be among the oldest habitation structures in the Levant. The site covers 21,000 square meters, and is the largest known Late Pleistocene site in the area.
Notably, the remains of brushwood structures dating to the Early Epipalaeolithic period have been found at Kharaneh IV. Tools and large concentrations of ochre and marine shells have also been found at the site.
In addition, woman's remains dated back to 19,200 years ago were discovered at Kharaneh IV in 2016, which might have been cremated, after being placed on top of a hut.
References
1955 archaeological discoveries
Archaeological sites in Jordan
Megasites | Kharaneh IV | [
"Physics",
"Mathematics"
] | 276 | [
"Quantity",
"Megasites",
"Physical quantities",
"Size"
] |
63,707,472 | https://en.wikipedia.org/wiki/ATPase%20Domain%203B | ATPase Domain 3B (ATAD3B) is a protein that in humans is encoded by the ATAD3B gene. ATAD3 is part of the AAA protein family. The function of ATAD3B is not yet well understood by the scientific community. In humans the gene is located at 1p36.33.
Function
ATAD3B is associated with the mitochondria. The C terminus is anchored in the mitochondrial inter membrane space.
The protein is linked with the pluripotency of stem cells. The ATAD3A gene is targeted by c-Myc which is one of four factors needed to create induced pluripotent stem (i-PS) cells from mouse embryonic fibroblasts(MEFs).
Its expression is linked to cell cycle function and tumor growth. When ATAD3B was overexpressed, cell duplication took an extra three hours by spending a longer time in G1 phase. Abnormal expression levels of ATAD3B has been linked to chemoresistance. Overexpression of ATAD3B was the found to be the strongest factor in breast cancer survival rates.
Characteristics
A mutation in the stop codon means that ATAD3B has a 62 amino acid longer UTR.
References
Induced stem cells
Proteins | ATPase Domain 3B | [
"Chemistry",
"Biology"
] | 265 | [
"Biomolecules by chemical classification",
"Stem cell research",
"Molecular biology",
"Proteins",
"Induced stem cells"
] |
78,184,477 | https://en.wikipedia.org/wiki/AO%200235%2B164 | AO 0235+164 is a BL Lacertae object (BL Lac object) located in the constellation of Aries, 7.5 billion light years from Earth. It has a redshift of 0.94. It was first discovered as an astronomical radio source by astronomers between 1967 and 1970, and formally identified with a red stellar object in 1975. Because of its extreme variability at both radio and optical wavelengths across the electromagnetic spectrum, this BL Lac object has been referred to as a blazar.
Description
AO 0235+164 is shown to be in a flaring state. It also had two major outbursts in 1975 and 1987. Another outburst occurred in 1997 the duration of which was on the order of 800 days with a maximum luminosity of 9.86 x 1047 erg s−1 suggesting a microlensing event scenario.
During a Fermi Large Area Telescope multi-wavelength observation between August 2008 and February 2009, the blazar underwent a high state showing intense gamma ray activity before falling to a low state. It displayed near-infrared flares in 2014 and 2017. By 2020, AO 0235+164 had brightened again, displaying an optical flare that reached its peak in 2021. However, when compared to previous flares, it is shown weaker despite emission at all wavelengths increasing from gamma rays to millimeter waves and its light curve exhibiting a multi-peak structure with sharp variability at high energies.
The optical brightness of AO 0235+164 is known to vary across different time scales ranging from a few hours in optical to a long period of time in radio. During the last three nights in January 2024, its brightness level significantly increased rapidly over 2 magnitudes in the R-band.
The source of AO 0235+164 is substantially resolved, however no structural position angle is distinguished . Additionally AO 0235+165 also contains a compact core with a weak extended structure located north-northwest from it, indicating a result of a small viewing angle found for the source. A component can be seen 0.7 mas away from the core with a position angle of = 7°. The radio components also have superluminal velocities reaching as fast as β ~ 30h−1 (h = H/100 km Mpc−1 s−1).
AO 0235+164 contains a supermassive black hole in its center. Based on analysis of a broad magnesium spectral line in its spectrum, the mass is 7.9 x 107 Mʘ. Alternatively, it might also contain a close binary black hole system with estimated similar masses of order of 1010 Mʘ with velocities of 104 and 5 x 103 kilometers per seconds.
References
External links
AO 0235+164 at SIMBAD
AO 0235+164 at NASA/IPAC Extragalactic Database
BL Lacertae objects
Aries (constellation)
Blazars
Quasars
Active galaxies
2823185
Astronomical objects discovered in 1975 | AO 0235+164 | [
"Astronomy"
] | 593 | [
"Aries (constellation)",
"Constellations"
] |
78,184,529 | https://en.wikipedia.org/wiki/Three%20dots%20%28Freemasonry%29 | Three dots (∴) also known as "tripunctual abbreviation" or "triple dot" is a symbol used all over the world in Freemasonry for abbreviations, signatures, and symbolic representation. The dots are typically arranged in a triangular pattern and carry multiple layers of meaning within Masonic tradition. The (∴) is used only for Masonic abbreviations, any non-masonic abbreviations must be written with a simple dot, as an example a date on a Masonic document could be written 6024 A∴L∴/2024 A.D.
History
The symbol has been used in Freemasonry since its earliest speculative days, at least as early as 1764, where it is found in the registers of La Sincerité Lodge in Besançon, France which stronlgy indicates an earlier use. While some attribute its widespread adoption to a circular issued by the Grand Orient de France on August 12, 1774, evidence shows earlier usage.
The symbol predates Freemasonry, appearing in various contexts:
Mathematical notation (as the "therefore" symbol)
Christian religious texts (representing the Trinity)
Usage
Abbreviations
The triple dot is used in Masonic writing to denote abbreviations of Masonic terms and titles:
B∴ or Bro∴ - Brother
L∴ - Lodge
"R∴W∴ John Smith" stands for "Right Worshipful John Smith" (an honorific indicating that Brother Smith is a Grand Lodge officer).
F∴&A∴M∴ - Free & Accepted Masons.
W∴M∴ - Worshipful Master
A∴L∴ - Anno Lucis
For plural forms, the initial letter is doubled:
BB∴ - Brothers
LL∴ - Lodges
Proper usage and protocol
The three dots symbol (∴) is an integral part of Masonic written tradition, used exclusively within Masonic context. All Master Masons are entitled to use these dots when writing Masonic terms, titles, or positions. The usage is strictly reserved for Masonic terminology and should not be applied to non-Masonic (profane) words or phrases.
A widespread misconception holds that the three dots are exclusively reserved for Grand Lodge usage. This error likely originated from historical circumstances, particularly following the Morgan Affair (1826). During this period, many individual Lodges abandoned or lost various traditional practices, while Grand Lodges maintained strict adherence to Masonic protocols and writing conventions. As Grand Lodges often became the primary preservers of these writing traditions while individual Lodges departed from them, particularly in the United States, this may have contributed to the misconception of exclusive Grand Lodge usage, but the three dots can be used for all Masonic communication, individual Lodges, messages, communications and attached to a signature by any Master Masons.
Format and common errors
The proper representation of the three dots is crucial for preserving Masonic written tradition. Several improper variations have emerged over time that should be avoided:
W∴M∴ (correct punctuation)
W:.M:. (incorrect punctuation)
W:M: (missing dot)
WM: (degraded form)
WM. (completely degraded form)
The correct format is W∴M∴, using the proper symbol (∴) rather than substituting periods or colons. This standardization plays a vital role in preserving Masonic tradition and ensures clear communication within the fraternity. Using the proper symbol helps prevent degradation of the traditional format and maintains the integrity of Masonic written communication.
The careful adherence to these writing conventions represents one of many traditional practices that distinguish Masonic correspondence from ordinary writing, emphasizing the importance of maintaining these standards in all Masonic communications.
Signature mark
Freemasons may incorporate the triple dot symbol into their signatures as a mark of identification. This practice became widespread in the late 18th and early 19th centuries and is reserved for Master Masons, it is used as a proof that the person has become an accomplished Master Mason.
Symbolism
The triple dot symbol carries multiple interpretations within Masonic tradition:
Symbol of mastery
Left dot: Entered Apprentice (Unbalance/left pillar)
Right dot: Fellow Craft (Unbalance/right pillar)
Top dot: Master Mason (Above the two and centered)
Philosophical interpretation
Left dot: Thesis/Affirmation
Right dot: Antithesis/Negation
Top dot: Synthesis/Solution
Other interpretations
The symbol is associated with various triadic concepts in Masonic philosophy:
Past, Present, and Future
Body, Soul, and Spirit
The three lights of the Lodge
The Trinity
Wisdom, Strength, and Beauty
See also
References
Freemasonry
Masonic symbolism
Symbols | Three dots (Freemasonry) | [
"Mathematics"
] | 869 | [
"Symbols"
] |
78,184,665 | https://en.wikipedia.org/wiki/Pin%20matrix | The Pin matrix is usually used for patching on non-modular synths. Generally inputs are on one axis and outputs on the other and a pin inserted where the two axes meet establishes a connection.
Disadvantages
The number of patches that can be made is limited and the proximity of signal wires in the matrix can cause crosstalk.
Synths that have used a pin matrix
ARP 2500
EMS Synthi 100
EMS VCS3
ETI International 4600
Maplin 5600
References
External links
Matrix switch options for modulation routing?, Mod Wiggler forum, October 2011 – warnings of circuit complexity
Yes, we have some bananas. We have some bananas today., Mod Wiggler forum, July 2010
Hinton Instruments SwitchMix background information
Making Audio PatchPanels and Making Patch Pins by Steven Thomas
Components | Pin matrix | [
"Technology"
] | 161 | [
"Components"
] |
78,184,948 | https://en.wikipedia.org/wiki/Tityus%20stigmurus%20toxin%201 | Tityus stigmurus toxin 1 (Tst1) is a neurotoxin found in the venom of the Brazilian scorpion, Tityus stigmurus. It acts on voltage-gated sodium channels (Navs), altering opening and inactivation voltages, recovery from inactivation, and overall current flow.
Etymology and source
Tst1 (alternatively PT-Mice-beta* NaTx6.3, Tst-gamma, toxin gamma-like of Tityus stigmurus) is a neurotoxic peptide which can be purified from the venom of the Brazilian scorpion, Tityus stigmurus.
The toxin name is derived from the name of the scorpion, with ‘Tst’ standing for Tityus stigmurus toxin. The ‘1’ was initially used by Becerril et al. to indicate that the toxin is 𝛾-like, however, Tst1 has since been found to be a β-toxin.
Chemistry
Tst1 consists of 61 amino acid residues, with an average molecular mass of 6981.8 Da. Tst1 has 96.7% identity with Ts1 and 93.4% with Tt1g, which are from Tityus serrulatus and Tityus trivittatus scorpions, respectively and both of which are also β-toxins.
Tst1 is part of the NaScTx family, which are neurotoxins that specifically target Nav channels. The 3D structure of the toxin has not yet been solved, however it can be predicted using Alphafold. The prediction suggests that the peptide is a cysteine-stabilised alpha/beta fold protein consisting of two α - helices and three β-sheets, with the last cysteine in the amino acid sequence being a cysteine amide.
Target and mode of action
Tst1 is a β-toxin, meaning that it interacts with the voltage sensing domains of Navs. Tst1 affects the activation voltage, inactivation voltage and recovery, and the overall current flow through the channels, with the largest effects being observed in Nav 1.3. Tst1 shifts the activation voltage of the channel towards more hyperpolarized potentials, with a shift of approximately -35 mV in Nav 1.3. It also shifts the steady-state inactivation potential by approximately -21 mV and delays recovery from inactivation by 10.69 ms. Finally, Tst1 reduces the current flow through these channels by 85.23%, in a dosage-dependent manner, with an IC50 of 8.79 nM. While Nav 1.3 is the most sensitive to Tst1, it is not the only isoform affected. Nav 1.2 and 1.4 were also significantly affected in all the parameters mentioned above, demonstrating that Tst1 activity is not specific to one isoform.
Toxicity
T. stigmurus is one of the most medically relevant species in its genus, particularly in the northeast region of Brazil. Symptoms of a T. stigmurus sting are variable, including localised pain, edema, erythema, paresthesia, headache, vomiting, and, in more severe cases, cardiac arrhythmias and shock. The effects of isolated Tst1 have not been determined, however, sodium channel toxins are the peptides mainly responsible for the neurotoxic symptoms of human envenomation, and so it is expected that Tst1 contributes to the neurotoxic symptoms in these cases.
References
Ion channel toxins
Peptides
Scorpion toxins | Tityus stigmurus toxin 1 | [
"Chemistry"
] | 753 | [
"Biomolecules by chemical classification",
"Peptides",
"Molecular biology"
] |
78,185,061 | https://en.wikipedia.org/wiki/RTX-III | RTX-III (neurotoxin-III,δ-SHTX-Hcr1a) is a neurotoxin peptide derived from the Sebae anemone Radianthus crispa. The toxin targets voltage-dependent sodium channels by preventing its complete inactivation, which can lead to a prolonged influx of sodium ions and depolarization of the cell's membrane.
Source
RTX-III is secreted by the sea anemone Radianthus crispa, also known as Heteractis crispa or Radianthus macrodactylus, which inhabits the Indian and Pacific Oceans.
Structure
Primary structure
The RTX-III neuropeptide consists of 48 amino acids cross-linked by three disulfide bridges.
The amino acid sequence of the neurotoxin-III is:
and its molecular mass is 5378.33 Da.
Secondary structure
Due to RTX-III's structural characteristics, this toxin is categorized as a type II sea anemone neurotoxin. The toxin has a guanidine group of Arg13 residues, as well as disulfide bridges, which may be important in maintaining its active conformation.
Homology
RTX-III is highly homologous with ShI, also a type II toxin, from the sea anemone Stichodactyla helianthus, whose sequence is 88% identical. RTX-III also shares significant homology with other toxins in the type II family, including RpII and RTX-VI.
Target
RTX-III is a Nav activator (also known as a sodium channel opener), which elicits changes in the functioning voltage-gated sodium channels of arthropods, insects and mammals. Research has shown evidence of affinity binding with various types of sodium channels. The toxin modulates the BgNav1 subtype of insects and the VdNav1 subtype of arachnoids. In mammals, it selectively modulates Nav 1.3 and Nav1.6 sodium channels.
All sea anemone toxins are thought to bind within binding site 3 of voltage-dependent sodium channels. The binding site for RTX-III, in particular, is proposed to overlap with that of the channel-inactivating scorpion α-toxins and spider δ-toxins, though it is not entirely identical.
Mode of action
RTX-III prevents or reduces the speed with which sodium channels are inactivated. The toxin inhibits the inactivation of the voltage-dependent sodium channels in a selective manner. The sodium channels may stay open for longer than normal, and consequently, the influx of sodium is prolonged. In turn, the influx of sodium may depolarize the membrane potential value towards a more positive membrane potential. Therefore, inactivation will be incomplete and less sensitive to any potential changes, slowing down the kinetics of sodium inactivation.
RTX-III differs from the conventional way in which sea anemones operate – an arginine residue being the center of binding with a sodium channel. In the case of neurotoxin-III, it is hypothesized that Arg13 may play a role in selecting specific sodium channel isoforms. However, these findings might only partially apply to RTX-III since a different, homologous toxin was investigated – RTX-VI.
Toxicity and potency
RTX-III presents a high toxicity in mammals. The LD50 for mice varies from 25 to 40 μg/kg, while the LD100 is 82 μg/kg in arthropods. Specific amino acid substitutions in the RTX-III sequence occur at the positions most toxic for mice.
The EC50 values of RTX-III also differ between mammals (381.8 nM) and insects/arthropods (978.1 nM). RTX-III displays a lower potency in arachnid and insect channels, with relatively high EC50 values. However, in mammalian channels the toxin may be more potent, showing smaller EC50 values. Since RTX-III is produced by a sea anemone, its main role is the effective modulation of arthropod sodium channels, so that the prey is immobilized but not necessarily killed.
RTX-III's toxic properties are distributed between its many functional groups, such as the Arg-13 guanidine group and the Gly-1 amino group.
References
Ion channel toxins
Neurotoxins
Sea anemone toxins
Peptides | RTX-III | [
"Chemistry"
] | 937 | [
"Biomolecules by chemical classification",
"Molecular biology",
"Neurochemistry",
"Neurotoxins",
"Peptides"
] |
78,185,903 | https://en.wikipedia.org/wiki/Ph%CE%B11%CE%B2 | Phα1β (also known as PnTx3-6; PhTx3-6; Phalpha1beta) is a peptide toxin that blocks various types of voltage-gated calcium channels (VGCCs) and is a specific receptor antagonist of the TRPA1 cation channel. The peptide is derived from the venom of the armed spider Phoneutria nigriventer and possesses wide-ranging analgesic and anti-nociceptive effects in animal models.
Source and Etymology
Phα1β is purified from the venom of Phoneutria nigriventer, commonly known as the “armed spider”. A recombinant peptide (CTK 01512-2) has been synthesized. CTK 01512-2 showed a level of efficacy and potency equivalent to Phα1β.
Chemistry
Phα1β (PhTx3-6) is the sixth isoform of the PhTx3 neurotoxin, with a mature peptide of 55 amino acids, including 12 cysteines. These cysteines form six disulfide bonds that contribute to the peptide's stable tertiary structure. The molecular mass, calculated from its mature amino acid sequence, is approximately 6045.03 Da.
The following sequence represents the mature peptide's amino acid sequence.
ACIPRGEICT DDCECCGCDN QCYCPPGSSL GIFKCSCAHA NKYFCNRKKE KCKKA
Target and mode of action
The peptide reversibly blocks a variety of voltage-gated calcium channels (VGCCs), including N-type (Cav2.2), R-type (Cav2.3), P/Q-type (Cav2.1), and L-type (Cav1.2) channels, with varying potencies that correspond to IC50 values of 122, 136, 263, and 607 nM, respectively. It induces a complete blockade of N-type-based currents and an incomplete blockade of R-, P/Q- and L-type-based currents. The exact mechanism by which Phα1β influences the functional properties of these ion channels remains unclear. However, it has been suggested that the peptide blocks VGCCs by physically occluding the pore, which could account for its varying effects across this family of channels. Furthermore, the toxin acts as a specific TRPA1 antagonist. Its affinity within this context has not yet been accurately determined.
Toxicity
Phα1β possesses wide-ranging analgesic and anti-nociceptive effects in animal models, that can be attributed to its modulatory action on VGCCs and TRPA1 receptors. Furthermore, it is known to be effective at doses that induce little to no side effects in animal models. While Phoneutria nigriventer venom is highly neurotoxic and can cause a range of symptoms that may include agitation, hypertension, perspiration, excessive salivation, nausea, profuse vomiting, lacrimation, somnolence, tachycardia, tachypnea, spasms, tremors, and priapism, the toxicity of Phα1β has not been sufficiently characterized to provide estimates of its LD50 or specific side effects.
Therapeutic use
Phα1β exhibits anti-nociceptive effects by inhibiting pro-nociceptive glutamate release induced by influx of calcium ions (Ca2+) or by inhibiting TRPA1 channels.
The cell bodies of sensory nerves, which are involved in neurogenic or inflammatory conditions, are primarily located in the Dorsal Root Ganglia (DRG). Phα1β attenuates the pain response by targeting synaptic transmission in these neurons in the following two ways.
1. Nociceptive modulation by voltage-gated calcium channels (VGCCs)
Nociception is modulated by VGCCs.
Upon activation of L, N, and P/Q type VGCCs in response to painful stimuli, glutamate is released. N-type channels (Cav2.2) respond most potently to painful stimuli. Thus, they are central to analgesic research as they constitute the primary source of Ca2+ influx, and are upregulated in response to chronic pain. Phα1β inhibits N-type channels, resulting in a decrease of glutamate influx and consequently reduced pain perception.
2. Nociceptive modulation by non-selective cation channels
Phα1β also affects the signal transmission of sensory neurons by targeting TRPA1 channels, which are non-selective cation channels predominantly found in the DRG. TRPA1 channels constitute a major pain conduction pathway. Phα1β acts as an antagonist for TRPA1, effectively inhibiting the calcium responses induced by TRPA1 agonists such as allyl isothiocyanate (AITC).
Compared to similar toxins (MVIIA, which is a ω-conotoxin), Phα1β has a significantly wider therapeutic index, no evident side effects in controlled settings in animal models, and longer-lasting analgesic effects. Phα1β achieves maximum pain relief comparable to other analogs (MVIIA), with a higher effective dose (ED50) and lower inhibitory dose (ID50), indicating enhanced safety and potency at lower concentrations. Importantly, Phα1β has the potential to prevent and reverse chronic pain conditions, such as those induced by complete Freund’s adjuvant (CFA), and alleviate symptoms of allodynia and hyperalgesia. Additionally, its analgesic and anti-inflammatory properties could also be utilized for pain treatment in cancer patients. Interestingly, Phα1β also appears to mitigate or even prevent symptoms in a mouse model of Huntington’s Disease, where it may exhibit neuroprotective effects and improve motor performance.
Phα1β is potentially useful for the treatment of various pain conditions, including acute and chronic inflammatory or neuropathic pain. Additionally, its potential may extend to neurodegenerative diseases such as Huntington's disease. Studies in human subjects would be required to explore its broader therapeutic applications and efficacy across different neurological conditions.
References
Ion channel toxins
Spider toxins
Neurotoxins | Phα1β | [
"Chemistry"
] | 1,316 | [
"Neurochemistry",
"Neurotoxins"
] |
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